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Daneshgar N, Lan R, Regnier M, Mackintosh SG, Venkatasubramanian R, Dai DF. Klotho enhances diastolic function in aged hearts through Sirt1-mediated pathways. GeroScience 2024; 46:4729-4741. [PMID: 38976132 PMCID: PMC11336011 DOI: 10.1007/s11357-024-01209-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Accepted: 05/16/2024] [Indexed: 07/09/2024] Open
Abstract
Aging leads to a progressive decline in cardiac function, increasing the risk of heart failure with preserved ejection fraction (HFpEF). This study elucidates the impact of α-Klotho, an anti-aging hormone, on cardiac diastolic dysfunction and explore its downstream mechanisms. Aged wild-type and heterozygous Klotho-deficient mice received daily injection of soluble α-Klotho (sKL) for 10 weeks, followed by a comprehensive assessment of heart function by echocardiography, intracardiac pressure catheter, exercise tolerance, and cardiac pathology. Our findings show that klotho deficiency accentuated cardiac hypertrophy, diastolic dysfunction, and exercise intolerance, while sKL treatment ameliorates these abnormalities and improves cardiac capillary densities. Downstream of klotho, we focused on the Sirtuin1 (Sirt1) signaling pathway to elucidate the potential underlying mechanism by which Klotho improves diastolic function. We found that decreased Klotho levels were linked with Sirt1 deficiency, whereas sKL treatment restored Sirt1 expression in aged hearts and mitigated the DNA damage response pathway activation. Through tandem mass tag proteomics and unbiased acetylomics analysis, we identified 220 significantly hyperacetylated lysine sites in critical cardiac proteins of aged hearts. We found that sKL supplementation attenuated age-dependent DNA damage and cardiac diastolic dysfunction. In contrast, Klotho deficiency significantly increased hyperacetylation of several crucial cardiac contractile proteins, potentially impairing ventricular relaxation and diastolic function, thus predisposing to HFpEF. These results suggest the potential benefit of sKL supplementation as a promising therapeutic strategy for combating HFpEF in aging.
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Affiliation(s)
- Nastaran Daneshgar
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Renny Lan
- UAMS, Arkansas Children's Nutrition Center, Little Rock, AR, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | - Dao-Fu Dai
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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2
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Mendoza-Carrera F, Farías-Basulto A, Gómez-García EF, Rizo de la Torre LDC, Cueto-Manzano AM, Cortés-Sanabria L, Pérez-Coria M, Vázquez-Rivera GE. Association of KLOTHO gene variants with metabolic and renal function parameters in Mexican patients living with type 2 diabetes. J Diabetes Metab Disord 2024; 23:1125-1131. [PMID: 38932797 PMCID: PMC11196432 DOI: 10.1007/s40200-024-01398-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/05/2024] [Indexed: 06/28/2024]
Abstract
Objective Type 2 diabetes (T2D) and high blood pressure are the main causes of chronic kidney disease (CKD) in adulthood. Both metabolic and oxidative stresses driven by hyperglycemia as well as genetic factors have been suggested as pathogenic causes of renal failure. Some single nucleotide variants (SNVs) on gene coding KLOTHO (KL) have been implicated in several clinical scenarios including hypertension, diabetes, and cardiovascular disease. The aim of this study was to analyze the association of rs1207568 (-395G > A), rs953614 (+ 1062T > G) and rs564481 (+ 1818 C > T) SNVs with metabolic and renal function parameters in Mexican patients living with type 2 diabetes. Methods A cross-sectional study was conducted in 637 Mexican patients with T2D, and/or hypertension without previous diagnosis of CKD. Anthropometric, metabolic, and renal function parameters were determined. Patients were genotyped for rs1207568, rs953614 and rs564481 SNVs and associations under a dominant genetic model were analyzed by logistic regression. Results For rs9536314, G-allele showed to be protective for hypo-HDL-C, albuminuria, and CKD. Carriers of minor allele of rs564481 had low odds for high glucose levels. No differences in genotype nor allele frequencies between the patients and the reference population were observed. Conclusion In Mexican patients living with type 2 diabetes, KL variant rs9536314 was found associated with low odds of hypo-HDL cholesterol, albuminuria and presence of CKD. Meanwhile the consensus of soluble KLOTHO measurement is reached, genetic variants in the KL gene could be considered as genetic markers for CKD susceptibility in patients at high-risk of vascular complications.
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Affiliation(s)
- Francisco Mendoza-Carrera
- División de Medicina Molecular, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano del Seguro Social (IMSS), Sierra Mojada # 800, Col. Independencia, 44340 Guadalajara, Jalisco Mexico
| | | | | | - Lourdes del Carmen Rizo de la Torre
- División de Medicina Molecular, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano del Seguro Social (IMSS), Sierra Mojada # 800, Col. Independencia, 44340 Guadalajara, Jalisco Mexico
| | - Alfonso Martin Cueto-Manzano
- Unidad de Investigación Biomédica 02, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Mexico
| | - Laura Cortés-Sanabria
- Unidad de Investigación Biomédica 02, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Mexico
| | - Mariana Pérez-Coria
- División de Medicina Molecular, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano del Seguro Social (IMSS), Sierra Mojada # 800, Col. Independencia, 44340 Guadalajara, Jalisco Mexico
| | - Gloria Elizabeth Vázquez-Rivera
- División de Medicina Molecular, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano del Seguro Social (IMSS), Sierra Mojada # 800, Col. Independencia, 44340 Guadalajara, Jalisco Mexico
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3
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Cararo-Lopes MM, Sadovnik R, Fu A, Suresh S, Gandu S, Firestein BL. Overexpression of α-Klotho isoforms promotes distinct Effects on BDNF-Induced Alterations in Dendritic Morphology. Mol Neurobiol 2024:10.1007/s12035-024-04171-y. [PMID: 38589756 DOI: 10.1007/s12035-024-04171-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 04/03/2024] [Indexed: 04/10/2024]
Abstract
α-Klotho (α-Kl) is a modulator of aging, neuroprotection, and cognition. Transcription of the Klotho gene produces two splice variants-a membrane protein (mKl), which can be cleaved and released into the extracellular milieu, and a truncated secreted form (sKl). Despite mounting evidence supporting a role for α-Kl in brain function, the specific roles of α-Kl isoforms in neuronal development remain elusive. Here, we examined α-Kl protein levels in rat brain and observed region-specific expression in the adult that differs between isoforms. In the developing hippocampus, levels of isoforms decrease after the third postnatal week, marking the end of the critical period for development. We overexpressed α-Kl isoforms in primary cultures of rat cortical neurons and evaluated effects on brain-derived neurotrophic factor (BDNF) signaling. Overexpression of either isoform attenuated BDNF-mediated signaling and reduced intracellular Ca2+ levels, with mKl promoting a greater effect. mKl or sKl overexpression in hippocampal neurons resulted in a partially overlapping reduction in secondary dendrite branching. Moreover, mKl overexpression increased primary dendrite number. BDNF treatment of neurons overexpressing sKl resulted in a dendrite branching phenotype similar to control neurons. In neurons overexpressing mKl, BDNF treatment restored branching of secondary and higher order dendrites close, but not distal, to the soma. Taken together, the data presented support the idea that sKl and mKl play distinct roles in neuronal development, and specifically, in dendrite morphogenesis.
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Affiliation(s)
- Marina Minto Cararo-Lopes
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Cell and Developmental Biology Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Ratchell Sadovnik
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Allen Fu
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Shradha Suresh
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Srinivasa Gandu
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Cell and Developmental Biology Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.
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4
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Schnicker NJ, Xu Z, Amir M, Gakhar L, Huang CL. Conformational landscape of soluble α-klotho revealed by cryogenic electron microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.02.583144. [PMID: 38496408 PMCID: PMC10942382 DOI: 10.1101/2024.03.02.583144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
α-Klotho (KLA) is a type-1 membranous protein that can associate with fibroblast growth factor receptor (FGFR) to form co-receptor for FGF23. The ectodomain of unassociated KLA is shed as soluble KLA (sKLA) to exert FGFR/FGF23-independent pleiotropic functions. The previously determined X-ray crystal structure of the extracellular region of sKLA in complex with FGF23 and FGFR1c suggests that sKLA functions solely as an on-demand coreceptor for FGF23. To understand the FGFR/FGF23-independent pleiotropic functions of sKLA, we investigated biophysical properties and structure of apo-sKLA. Mass photometry revealed that sKLA can form a stable structure with FGFR and/or FGF23 as well as sKLA dimer in solution. Single particle cryogenic electron microscopy (cryo-EM) supported the dimeric structure of sKLA. Cryo-EM further revealed a 3.3Å resolution structure of apo-sKLA that overlays well with its counterpart in the ternary complex with several distinct features. Compared to the ternary complex, the KL2 domain of apo-sKLA is more flexible. 3D variability analysis revealed that apo-sKLA adopts conformations with different KL1-KL2 interdomain bending and rotational angles. The potential multiple forms and shapes of sKLA support its role as FGFR-independent hormone with pleiotropic functions. A comprehensive understanding of the sKLA conformational landscape will provide the foundation for developing klotho-related therapies for diseases.
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Affiliation(s)
- Nicholas J. Schnicker
- Protein and Crystallography Facility, University of Iowa Carver College of Medicine, Iowa City, Iowa, 52242, USA
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, 52242, USA
| | - Zhen Xu
- Protein and Crystallography Facility, University of Iowa Carver College of Medicine, Iowa City, Iowa, 52242, USA
| | - Mohammad Amir
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, 52242, USA
| | - Lokesh Gakhar
- Protein and Crystallography Facility, University of Iowa Carver College of Medicine, Iowa City, Iowa, 52242, USA
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, 52242, USA
| | - Chou-Long Huang
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, 52242, USA
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5
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Turner ME, Beck L, Hill Gallant KM, Chen Y, Moe OW, Kuro-o M, Moe S, Aikawa E. Phosphate in Cardiovascular Disease: From New Insights Into Molecular Mechanisms to Clinical Implications. Arterioscler Thromb Vasc Biol 2024; 44:584-602. [PMID: 38205639 PMCID: PMC10922848 DOI: 10.1161/atvbaha.123.319198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Hyperphosphatemia is a common feature in patients with impaired kidney function and is associated with increased risk of cardiovascular disease. This phenomenon extends to the general population, whereby elevations of serum phosphate within the normal range increase risk; however, the mechanism by which this occurs is multifaceted, and many aspects are poorly understood. Less than 1% of total body phosphate is found in the circulation and extracellular space, and its regulation involves multiple organ cross talk and hormones to coordinate absorption from the small intestine and excretion by the kidneys. For phosphate to be regulated, it must be sensed. While mostly enigmatic, various phosphate sensors have been elucidated in recent years. Phosphate in the circulation can be buffered, either through regulated exchange between extracellular and cellular spaces or through chelation by circulating proteins (ie, fetuin-A) to form calciprotein particles, which in themselves serve a function for bulk mineral transport and signaling. Either through direct signaling or through mediators like hormones, calciprotein particles, or calcifying extracellular vesicles, phosphate can induce various cardiovascular disease pathologies: most notably, ectopic cardiovascular calcification but also left ventricular hypertrophy, as well as bone and kidney diseases, which then propagate phosphate dysregulation further. Therapies targeting phosphate have mostly focused on intestinal binding, of which appreciation and understanding of paracellular transport has greatly advanced the field. However, pharmacotherapies that target cardiovascular consequences of phosphate directly, such as vascular calcification, are still an area of great unmet medical need.
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Affiliation(s)
- Mandy E. Turner
- Division of Cardiovascular Medicine, Department of Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Laurent Beck
- Nantes Université, CNRS, Inserm, l’institut du thorax, F-44000 Nantes, France
| | - Kathleen M Hill Gallant
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yabing Chen
- Department of Pathology, University of Alabama at Birmingham
- Research Department, Veterans Affairs Birmingham Medical Center, Birmingham, AL, USA
| | - Orson W Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Makoto Kuro-o
- Division of Anti-aging Medicine, Center for Molecular Medicine, Jichi Medical University 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Sharon Moe
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elena Aikawa
- Division of Cardiovascular Medicine, Department of Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Division of Cardiovascular Medicine, Department of Medicine, Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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6
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Martín-Vírgala J, Martín-Carro B, Fernández-Villabrille S, Ruiz-Torres MP, Gómez-Alonso C, Rodríguez-García M, Fernández-Martín JL, Alonso-Montes C, Panizo S, Cannata-Andía JB, Naves-Díaz M, Carrillo-López N. Soluble Klotho, a Potential Biomarker of Chronic Kidney Disease-Mineral Bone Disorders Involved in Healthy Ageing: Lights and Shadows. Int J Mol Sci 2024; 25:1843. [PMID: 38339121 PMCID: PMC10855561 DOI: 10.3390/ijms25031843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/23/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024] Open
Abstract
Shortly after the discovery of Klotho, interest grew in its potential role in chronic kidney disease (CKD). There are three isoforms of the Klotho protein: αKlotho, βKlotho and γKlotho. This review will focus on αKlotho due to its relevance as a biomarker in CKD. αKlotho is synthesized mainly in the kidneys, but it can be released into the bloodstream and urine as soluble Klotho (sKlotho), which undertakes systemic actions, independently or in combination with FGF23. It is usually accepted that sKlotho levels are reduced early in CKD and that lower levels of sKlotho might be associated with the main chronic kidney disease-mineral bone disorders (CKD-MBDs): cardiovascular and bone disease. However, as results are inconsistent, the applicability of sKlotho as a CKD-MBD biomarker is still a matter of controversy. Much of the inconsistency can be explained due to low sample numbers, the low quality of clinical studies, the lack of standardized assays to assess sKlotho and a lack of consensus on sample processing, especially in urine. In recent decades, because of our longer life expectancies, the prevalence of accelerated-ageing diseases, such as CKD, has increased. Exercise, social interaction and caloric restriction are considered key factors for healthy ageing. While exercise and social interaction seem to be related to higher serum sKlotho levels, it is not clear whether serum sKlotho might be influenced by caloric restriction. This review focuses on the possible role of sKlotho as a biomarker in CKD-MBD, highlighting the difference between solid knowledge and areas requiring further research, including the role of sKlotho in healthy ageing.
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Affiliation(s)
- Julia Martín-Vírgala
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
| | - Beatriz Martín-Carro
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
| | - Sara Fernández-Villabrille
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
| | - María Piedad Ruiz-Torres
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
- Área 5—Fisiología y Fisiopatología Renal y Vascular del Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Physiology Unit, Department of Systems Biology, Facultad de Medicina y Ciencias de la Salud, Universidad de Alcalá, 28871 Alcalá de Henares, Spain
| | - Carlos Gómez-Alonso
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Bone and Mineral Research Unit, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
| | - Minerva Rodríguez-García
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
- Nephrology Unit, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
| | - José Luis Fernández-Martín
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
- Bone and Mineral Research Unit, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
| | - Cristina Alonso-Montes
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
| | - Sara Panizo
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
| | - Jorge B. Cannata-Andía
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
- Department of Medicine, Universidad de Oviedo, 33011 Oviedo, Spain
| | - Manuel Naves-Díaz
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
- Bone and Mineral Research Unit, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
| | - Natalia Carrillo-López
- Metabolismo Óseo, Vascular y Enfermedades Inflamatorias Crónicas, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS2040, Kidney Disease), 28040 Madrid, Spain;
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Edmonston D, Grabner A, Wolf M. FGF23 and klotho at the intersection of kidney and cardiovascular disease. Nat Rev Cardiol 2024; 21:11-24. [PMID: 37443358 DOI: 10.1038/s41569-023-00903-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/15/2023]
Abstract
Cardiovascular disease is the leading cause of death in patients with chronic kidney disease (CKD). As CKD progresses, CKD-specific risk factors, such as disordered mineral homeostasis, amplify traditional cardiovascular risk factors. Fibroblast growth factor 23 (FGF23) regulates mineral homeostasis by activating complexes of FGF receptors and transmembrane klotho co-receptors. A soluble form of klotho also acts as a 'portable' FGF23 co-receptor in tissues that do not express klotho. In progressive CKD, rising circulating FGF23 levels in combination with decreasing kidney expression of klotho results in klotho-independent effects of FGF23 on the heart that promote left ventricular hypertrophy, heart failure, atrial fibrillation and death. Emerging data suggest that soluble klotho might mitigate some of these effects via several candidate mechanisms. More research is needed to investigate FGF23 excess and klotho deficiency in specific cardiovascular complications of CKD, but the pathophysiological primacy of FGF23 excess versus klotho deficiency might never be precisely resolved, given the entangled feedback loops that they share. Therefore, randomized trials should prioritize clinical practicality over scientific certainty by targeting disordered mineral homeostasis holistically in an effort to improve cardiovascular outcomes in patients with CKD.
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Affiliation(s)
- Daniel Edmonston
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | - Alexander Grabner
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Myles Wolf
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA.
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
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8
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Johnson AK, McCurdy VJ, Gray-Edwards HL, Maguire AS, Cochran JN, Gross AL, Skinner HE, Randle AN, Shirley JL, Brunson BL, Bradbury AM, Leroy SG, Hwang M, Rockwell HE, Cox NR, Baker HJ, Seyfried TN, Sena-Esteves M, Martin DR. Life-Limiting Peripheral Organ Dysfunction in Feline Sandhoff Disease Emerges after Effective CNS Gene Therapy. Ann Neurol 2023; 94:969-986. [PMID: 37526361 DOI: 10.1002/ana.26756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 05/15/2023] [Accepted: 07/27/2023] [Indexed: 08/02/2023]
Abstract
OBJECTIVE GM2 gangliosidosis is usually fatal by 5 years of age in its 2 major subtypes, Tay-Sachs and Sandhoff disease. First reported in 1881, GM2 gangliosidosis has no effective treatment today, and children succumb to the disease after a protracted neurodegenerative course and semi-vegetative state. This study seeks to further develop adeno-associated virus (AAV) gene therapy for human translation. METHODS Cats with Sandhoff disease were treated by intracranial injection of vectors expressing feline β-N-acetylhexosaminidase, the enzyme deficient in GM2 gangliosidosis. RESULTS Hexosaminidase activity throughout the brain and spinal cord was above normal after treatment, with highest activities at the injection sites (thalamus and deep cerebellar nuclei). Ganglioside storage was reduced throughout the brain and spinal cord, with near complete clearance in many regions. While untreated cats with Sandhoff disease lived for 4.4 ± 0.6 months, AAV-treated cats lived to 19.1 ± 8.6 months, and 3 of 9 cats lived >21 months. Correction of the central nervous system was so effective that significant increases in lifespan led to the emergence of otherwise subclinical peripheral disease, including megacolon, enlarged stomach and urinary bladder, soft tissue spinal cord compression, and patellar luxation. Throughout the gastrointestinal tract, neurons of the myenteric and submucosal plexuses developed profound pathology, demonstrating that the enteric nervous system was inadequately treated. INTERPRETATION The vector formulation in the current study effectively treats neuropathology in feline Sandhoff disease, but whole-body targeting will be an important consideration in next-generation approaches. ANN NEUROL 2023;94:969-986.
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Affiliation(s)
- Aime K Johnson
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Victoria J McCurdy
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Heather L Gray-Edwards
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Anne S Maguire
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - J Nicholas Cochran
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Amanda L Gross
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Haleigh E Skinner
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Ashley N Randle
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Jamie L Shirley
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Brandon L Brunson
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Allison M Bradbury
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Stanley G Leroy
- Department of Neurology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Misako Hwang
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Hannah E Rockwell
- Biology Department, Boston College, Chestnut Hill, Massachusetts, USA
| | - Nancy R Cox
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Henry J Baker
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Thomas N Seyfried
- Biology Department, Boston College, Chestnut Hill, Massachusetts, USA
| | - Miguel Sena-Esteves
- Department of Neurology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Douglas R Martin
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
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9
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Puddu A, Maggi DC. Klotho: A new therapeutic target in diabetic retinopathy? World J Diabetes 2023; 14:1027-1036. [PMID: 37547589 PMCID: PMC10401458 DOI: 10.4239/wjd.v14.i7.1027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/12/2023] [Accepted: 05/22/2023] [Indexed: 07/12/2023] Open
Abstract
Klotho (Kl) is considered an antiaging gene, mainly for the inhibition of the insulin-like growth factor-1 signaling. Kl exists as full-length transmembrane, which acts as co-receptor for fibroblast growth factor receptor, and in soluble forms (sKl). The sKl may exert pleiotropic effects on organs and tissues by regulating several pathways involved in the pathogenesis of diseases associated with oxidative and inflammatory state. In diabetic Patients, serum levels of Kl are significantly decreased compared to healthy subjects, and are related to duration of diabetes. In diabetic retinopathy (DR), one of the most common microvascular complications of type 2 diabetes, serum Kl levels are negatively correlated with progression of the disease. A lot of evidences showed that Kl regulates several mechanisms involved in maintaining homeostasis and functions of retinal cells, including phagocytosis, calcium signaling, secretion of vascular endothelial growth factor A (VEGF-A), maintenance of redox status, and melanin biosynthesis. Experimental data have been shown that Kl exerts positive effects on several mechanisms involved in onset and progression of DR. In particular, treatment with Kl: (1) Prevents apoptosis induced by oxidative stress in human retinal endothelial cells and in retinal pigment epithelium (RPE) cells; (2) reduces secretion of VEGF-A by RPE cells; and (3) decreases subretinal fibrosis and preserves autophagic activity. Therefore, Kl may become a novel biomarker and a good candidate for the treatment of DR.
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Affiliation(s)
- Alessandra Puddu
- Department of Internal Medicine and Medical Specialties, University of Genova, Genova 16132, Italy
| | - Davide Carlo Maggi
- Department of Internal Medicine and Medical Specialties, University of Genova, Genova 16132, Italy
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10
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Jin HS, Jung D. The KL genetic polymorphisms Associated with type 2 diabetes Mellitus. Indian J Clin Biochem 2023; 38:385-392. [PMID: 37234182 PMCID: PMC10205947 DOI: 10.1007/s12291-022-01057-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 06/06/2022] [Indexed: 10/15/2022]
Abstract
Growing number of research studies have shown that an anti-ageing gene Klotho (KL) is closely associated with Type 2 Diabetes Mellitus (T2DM). In this study, the association is genetically analyzed with single nucleotide polymorphism (SNP) of KL found in T2DM case of an Asian cohort. KL SNP information was obtained from a big database of the Korean Association Resource (KARE) from which 20 KL SNPs were available. Statistical analyses were conducted based on the 3 genetic models, such as additive, dominant, and recessive. Of the 20 KL SNPs, 12 SNPs were found to be significantly associated with T2DM in both of additive and dominant models. Odds ratios of the KL SNPs indicate increased susceptibility to T2DM in additive and dominant models. Significant association of KL with T2DM was further analyzed using imputed KL SNPs from HapMap reference data of the Eastern population. The statistically significant KL SNPs including the imputed SNPs distributed evenly over the KL gene area. The results in this study suggest klotho is a major player in the development of T2DM and the KL SNPs found in the case could be a risk marker of T2DM in the cohort.
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Affiliation(s)
- Hyun-Seok Jin
- Department of Biomedical Laboratory Science, College of Life and Health Sciences, Hoseo University, 31499 Asan, Chungnam Republic of Korea
| | - Dongju Jung
- Department of Biomedical Laboratory Science, College of Life and Health Sciences, Hoseo University, 31499 Asan, Chungnam Republic of Korea
- Klotho Sciences Corporation, Healthcare Innovation Park, Seoul National University Bundang Hospital Complex, Seongnam, Gyenggi Republic of Korea
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11
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Thomas SM, Li Q, Faul C. Fibroblast growth factor 23, klotho and heparin. Curr Opin Nephrol Hypertens 2023; 32:313-323. [PMID: 37195242 PMCID: PMC10241433 DOI: 10.1097/mnh.0000000000000895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
PURPOSE OF REVIEW Fibroblast growth factor (FGF) 23 is a bone-derived hormone that regulates phosphate and vitamin D metabolism by targeting the kidney. When highly elevated, such as in chronic kidney disease (CKD), FGF23 can also target the heart and induce pathologic remodeling. Here we discuss the mechanisms that underlie the physiologic and pathologic actions of FGF23, with focus on its FGF receptors (FGFR) and co-receptors. RECENT FINDINGS Klotho is a transmembrane protein that acts as an FGFR co-receptor for FGF23 on physiologic target cells. Klotho also exists as a circulating variant, and recent studies suggested that soluble klotho (sKL) can mediate FGF23 effects in cells that do not express klotho. Furthermore, it has been assumed that the actions of FGF23 do not require heparan sulfate (HS), a proteoglycan that acts as a co-receptor for other FGF isoforms. However, recent studies revealed that HS can be part of the FGF23:FGFR signaling complex and modulate FGF23-induced effects. SUMMARY sKL and HS have appeared as circulating FGFR co-receptors that modulate the actions of FGF23. Experimental studies suggest that sKL protects from and HS accelerates CKD-associated heart injury. However, the in vivo relevance of these findings is still speculative.
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Affiliation(s)
- S Madison Thomas
- Division of Nephrology and Section of Mineral Metabolism, Department of Medicine, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
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12
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Single-Molecule Imaging of Ganglioside Probes in Living Cell Plasma Membranes. Methods Mol Biol 2023; 2613:215-227. [PMID: 36587082 DOI: 10.1007/978-1-0716-2910-9_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Gangliosides play a variety of physiological roles and are one of the most important lipid raft constituents. However, their dynamic behaviors have scarcely been investigated in living cells because of the lack of fluorescent probes that behave like their parental molecules. Recently, fluorescent ganglioside probes that mimic native ganglioside behaviors have been developed. In this chapter, I discuss the recent advances in research related to the lateral localization and dynamic behaviors of gangliosides in the plasma membranes of living cells.
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13
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Vasques J, de Jesus Gonçalves R, da Silva-Junior A, Martins R, Gubert F, Mendez-Otero R. Gangliosides in nervous system development, regeneration, and pathologies. Neural Regen Res 2023. [PMID: 35799513 PMCID: PMC9241395 DOI: 10.4103/1673-5374.343890] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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14
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Yanucil C, Kentrup D, Campos I, Czaya B, Heitman K, Westbrook D, Osis G, Grabner A, Wende AR, Vallejo J, Wacker MJ, Navarro-Garcia JA, Ruiz-Hurtado G, Zhang F, Song Y, Linhardt RJ, White K, Kapiloff M, Faul C. Soluble α-klotho and heparin modulate the pathologic cardiac actions of fibroblast growth factor 23 in chronic kidney disease. Kidney Int 2022; 102:261-279. [PMID: 35513125 PMCID: PMC9329240 DOI: 10.1016/j.kint.2022.03.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 01/03/2023]
Abstract
Fibroblast growth factor (FGF) 23 is a phosphate-regulating hormone that is elevated in patients with chronic kidney disease and associated with cardiovascular mortality. Experimental studies showed that elevated FGF23 levels induce cardiac hypertrophy by targeting cardiac myocytes via FGF receptor isoform 4 (FGFR4). A recent structural analysis revealed that the complex of FGF23 and FGFR1, the physiologic FGF23 receptor in the kidney, includes soluble α-klotho (klotho) and heparin, which both act as co-factors for FGF23/FGFR1 signaling. Here, we investigated whether soluble klotho, a circulating protein with cardio-protective properties, and heparin, a factor that is routinely infused into patients with kidney failure during the hemodialysis procedure, regulate FGF23/FGFR4 signaling and effects in cardiac myocytes. We developed a plate-based binding assay to quantify affinities of specific FGF23/FGFR interactions and found that soluble klotho and heparin mediate FGF23 binding to distinct FGFR isoforms. Heparin specifically mediated FGF23 binding to FGFR4 and increased FGF23 stimulatory effects on hypertrophic growth and contractility in isolated cardiac myocytes. When repetitively injected into two different mouse models with elevated serum FGF23 levels, heparin aggravated cardiac hypertrophy. We also developed a novel procedure for the synthesis and purification of recombinant soluble klotho, which showed anti-hypertrophic effects in FGF23-treated cardiac myocytes. Thus, soluble klotho and heparin act as independent FGF23 co-receptors with opposite effects on the pathologic actions of FGF23, with soluble klotho reducing and heparin increasing FGF23-induced cardiac hypertrophy. Hence, whether heparin injections during hemodialysis in patients with extremely high serum FGF23 levels contribute to their high rates of cardiovascular events and mortality remains to be studied.
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Affiliation(s)
- Christopher Yanucil
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dominik Kentrup
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA.,Division of Nephrology and Hypertension, Center for Translational Metabolism and Health, Feinberg Cardiovascular and Renal Research Institute, Northwestern University, Chicago, IL, USA
| | - Isaac Campos
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brian Czaya
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kylie Heitman
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - David Westbrook
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gunars Osis
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexander Grabner
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Adam R. Wende
- Division of Molecular & Cellular Pathology, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julian Vallejo
- Department of Molecular Biosciences, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Michael J. Wacker
- Department of Molecular Biosciences, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Jose Alberto Navarro-Garcia
- Cardiorenal Translational Laboratory, Institute of Research, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Gema Ruiz-Hurtado
- Cardiorenal Translational Laboratory, Institute of Research, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Fuming Zhang
- Departments of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Yuefan Song
- Departments of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Robert J. Linhardt
- Departments of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Departments of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Kenneth White
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Michael Kapiloff
- Departments of Ophthalmology and Medicine, Stanford Cardiovascular Institute, Stanford University, Palo Alto, CA, USA
| | - Christian Faul
- Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA.
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15
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Isakova T, Yanucil C, Faul C. A Klotho-Derived Peptide as a Possible Novel Drug to Prevent Kidney Fibrosis. Am J Kidney Dis 2022; 80:285-288. [PMID: 35469964 DOI: 10.1053/j.ajkd.2022.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 01/27/2023]
Affiliation(s)
- Tamara Isakova
- Division of Nephrology and Hypertension, Department of Medicine and Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
| | - Christopher Yanucil
- Section of Mineral Metabolism, Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama
| | - Christian Faul
- Section of Mineral Metabolism, Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama
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16
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New concepts in regulation and function of the FGF23. Clin Exp Med 2022:10.1007/s10238-022-00844-x. [PMID: 35708778 DOI: 10.1007/s10238-022-00844-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/20/2022] [Indexed: 11/03/2022]
Abstract
In comparison to the regulation of calcium homeostasis, which has been widely studied over the last several decades, phosphate homeostasis is little understood. The parathyroid hormone (PTH)/vitamin D axis has traditionally been used as a conceptual framework for understanding mineral metabolism. Recently, the fundamental regulator of phosphate homeostasis, fibroblast growth factor 23 (FGF23), which is produced by osteocytes and is involved in the hormonal bone-parathyroid-kidney axis, has attracted more attention. The secretion of FGF23 is controlled by diet, serum phosphate levels, PTH, and 1,25(OH)2 vitamin D. FGF-23, the FGF receptors and the obligate co-receptor α-Klotho work in concert to affect FGF-23 actions on targeted organs. Despite all efforts to investigate pleotropic effects of FGF23 in various endocrine organs, many aspects of the regulation and functions of FGF23 and the exact crosstalk among FGF23, serum phosphate, calcium, PTH, and vitamin D in the regulation of mineral homeostasis remain unclear; much efforts need to be established before it can be moved toward therapeutic applications. In this regard, we provide a brief overview of the novel findings in the regulation and function of FGF23 and refer to related questions and hypotheses not answered yet, which can be a window for future projects. We also focus on the current knowledge about the role of FGF23 obtained from our researches in recent years.
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17
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Baccam GC, Xie J, Jin X, Park H, Wang B, Husson H, Ibraghimov-Beskrovnaya O, Huang CL. Glucosylceramide synthase inhibition protects against cardiac hypertrophy in chronic kidney disease. Sci Rep 2022; 12:9340. [PMID: 35660779 PMCID: PMC9167280 DOI: 10.1038/s41598-022-13390-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/09/2022] [Indexed: 11/20/2022] Open
Abstract
A significant population of patients with chronic kidney disease (CKD) develops cardiac hypertrophy, which can lead to heart failure and sudden cardiac death. Soluble klotho (sKL), the shed ectodomain of the transmembrane protein klotho, protects the heart against hypertrophic growth. We have shown that sKL protects the heart by regulating the formation and function of lipid rafts by targeting the sialic acid moiety of gangliosides, GM1/GM3. Reduction in circulating sKL contributes to an increased risk of cardiac hypertrophy in mice. sKL replacement therapy has been considered but its use is limited by the inability to mass produce the protein. Therefore, alternative methods to protect the heart are proposed. Glucosylation of ceramide catalyzed by glucosylceramide synthase is the entry step for the formation of gangliosides. Here we show that oral administration of a glucosylceramide synthase inhibitor (GCSi) reduces plasma and heart tissue glycosphingolipids, including gangliosides. Administration of GCSi is protective in two mouse models of cardiac stress-induction, one with isoproterenol overstimulation and the other with 5/6 nephrectomy-induced CKD. Treatment with GCSi does not alter the severity of renal dysfunction and hypertension in CKD. These results provide proof of principle for targeting glucosylceramide synthase to decrease gangliosides as a treatment for cardiac hypertrophy. They also support the hypothesis that sKL protects the heart by targeting gangliosides.
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Affiliation(s)
- Gabriel C Baccam
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, 200 Hawkins Drive, E300 GH, Iowa City, IA, 52242-1081, USA
| | - Jian Xie
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, 200 Hawkins Drive, E300 GH, Iowa City, IA, 52242-1081, USA
| | - Xin Jin
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, 200 Hawkins Drive, E300 GH, Iowa City, IA, 52242-1081, USA
| | - Hyejung Park
- US Early Development, Synthetics Platform, Global CMC Development, Sanofi, Waltham, MA, 02451, USA
| | - Bing Wang
- US Early Development, Synthetics Platform, Global CMC Development, Sanofi, Waltham, MA, 02451, USA
| | - Hervé Husson
- Genomic Medicine Unit, Sanofi, Framingham, MA, 01701, USA
| | - Oxana Ibraghimov-Beskrovnaya
- Rare and Neurologic Diseases, Sanofi, Framingham, MA, 01701, USA
- Dyne Therapeutics, 1560 Trapelo Road, Waltham, MA, 20451, USA
| | - Chou-Long Huang
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, 200 Hawkins Drive, E300 GH, Iowa City, IA, 52242-1081, USA.
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18
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Fu Y, He Y, Phan K, Pickford R, Kim YB, Dzamko N, Halliday GM, Kim WS. Sex-specific lipid dysregulation in the Abca7 knockout mouse brain. Brain Commun 2022; 4:fcac120. [PMID: 35620166 PMCID: PMC9127619 DOI: 10.1093/braincomms/fcac120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/06/2022] [Accepted: 05/09/2022] [Indexed: 11/12/2022] Open
Abstract
Alzheimer's disease is a devastating neurodegenerative disease that affects more women than men. The pathomechanism underlying the sex disparity, especially in the brain, is unclear. ABCA7 is one of the strongest susceptibility genes for Alzheimer's disease. It mediates the transport of lipids across membranes and is associated with pathways related to amyloid-β neuropathology. However, the role of ABCA7 in the regulation of brain lipids is largely unknown. Sex-specific differences in the pathological link between brain lipid dysregulation and amyloid-β are also unknown. Here, we undertook quantitative discovery lipidomics of male and female Abca7 knockout (n = 52) and wild type (n = 35) mouse brain using sophisticated liquid chromatography/mass spectrometry. We identified 61 lipid subclasses in the mouse brain and found sex-specific differences in lipids that were altered with Abca7 deletion. The altered lipids belong to cellular pathways that control cell signalling, sterol metabolism, mitochondrial function and neuroprotection. We also investigated the relationship between lipids and amyloid-β levels in the Abca7 knockout mice and found elevated free cholesterol only in female mice that was significantly correlated with amyloid-β42 levels. In male Abca7 knockout mice, the neuroprotective ganglioside GD1a levels were elevated and inversely correlated with amyloid-β42 levels. Collectively, these results demonstrate that Abca7 deletion leads to sex-specific lipid dysregulation in the brain, providing insight into the underlying sex disparity in the aetiology of Alzheimer's disease.
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Affiliation(s)
- YuHong Fu
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Ying He
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Katherine Phan
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, NSW, Australia
| | - Young-Bum Kim
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Nicolas Dzamko
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Glenda M. Halliday
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, University of New South Wales & Neuroscience Research Australia, Sydney, NSW, Australia
| | - Woojin Scott Kim
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, University of New South Wales & Neuroscience Research Australia, Sydney, NSW, Australia
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19
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Podbielska M, Ariga T, Pokryszko-Dragan A. Sphingolipid Players in Multiple Sclerosis: Their Influence on the Initiation and Course of the Disease. Int J Mol Sci 2022; 23:ijms23105330. [PMID: 35628142 PMCID: PMC9140914 DOI: 10.3390/ijms23105330] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/05/2022] [Accepted: 05/08/2022] [Indexed: 02/06/2023] Open
Abstract
Sphingolipids (SLs) play a significant role in the nervous system, as major components of the myelin sheath, contributors to lipid raft formation that organize intracellular processes, as well as active mediators of transport, signaling and the survival of neurons and glial cells. Alterations in SL metabolism and content are observed in the course of central nervous system diseases, including multiple sclerosis (MS). In this review, we summarize the current evidence from studies on SLs (particularly gangliosides), which may shed new light upon processes underlying the MS background. The relevant aspects of these studies include alterations of the SL profile in MS, the role of antibodies against SLs and complexes of SL-ligand-invariant NKT cells in the autoimmune response as the core pathomechanism in MS. The contribution of lipid-raft-associated SLs and SL-laden extracellular vesicles to the disease etiology is also discussed. These findings may have diagnostic implications, with SLs and anti-SL antibodies as potential markers of MS activity and progression. Intriguing prospects of novel therapeutic options in MS are associated with SL potential for myelin repair and neuroprotective effects, which have not been yet addressed by the available treatment strategies. Overall, all these concepts are promising and encourage the further development of SL-based studies in the field of MS.
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Affiliation(s)
- Maria Podbielska
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
- Laboratory of Microbiome Immunobiology, Ludwik Hirszfeld Institute of Immunology & Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland
- Correspondence: ; Tel.: +48-71-370-99-12
| | - Toshio Ariga
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
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20
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Lee H, Choi SQ. Sphingomyelinase-Mediated Multitimescale Clustering of Ganglioside GM1 in Heterogeneous Lipid Membranes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2101766. [PMID: 34473415 PMCID: PMC8529493 DOI: 10.1002/advs.202101766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/19/2021] [Indexed: 05/05/2023]
Abstract
Several signaling processes in the plasma membrane are intensified by ceramides that are formed by sphingomyelinase-mediated hydrolysis of sphingomyelin. These ceramides trigger clustering of signaling-related biomolecules, but how they concentrate such biomolecules remains unclear. Here, the spatiotemporal localization of ganglioside GM1, a glycolipid receptor involved in signaling, during sphingomyelinase-mediated hydrolysis is described. Real-time visualization of the dynamic remodeling of the heterogeneous lipid membrane that occurs due to sphingomyelinase action is used to examine GM1 clustering, and unexpectedly, it is found that it is more complex than previously thought. Specifically, lipid membranes generate two distinct types of condensed GM1: 1) rapidly formed but short-lived GM1 clusters that are formed in ceramide-rich domains nucleated from the liquid-disordered phase; and 2) late-onset yet long-lasting, high-density GM1 clusters that are formed in the liquid-ordered phase. These findings suggest that multiple pathways exist in a plasma membrane to synergistically facilitate the rapid amplification and persistence of signals.
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Affiliation(s)
- Hyun‐Ro Lee
- Department of Chemical and Biomolecular EngineeringKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Siyoung Q. Choi
- Department of Chemical and Biomolecular EngineeringKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- KAIST Institute for the NanoCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
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21
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Epstein M, Freundlich M. The intersection of Mineralocorticoid Receptor (MR) activation and the FGF23 - Klotho cascade. A Duopoly that promotes renal and cardiovascular injury. Nephrol Dial Transplant 2021; 37:211-221. [PMID: 34459924 DOI: 10.1093/ndt/gfab254] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 12/17/2022] Open
Abstract
The nexus of CKD and cardiovascular disease (CVD) amplifies the morbidity and mortality of CKD, emphasizing the need for defining and establishing therapeutic initiatives to modify and abrogate the progression of CKD and concomitant CV risks. In addition to the traditional CV risk factors, disturbances of mineral metabolism are specific risk factors that contribute to the excessive CV mortality in patients with CKD. These risk factors include dysregulations of circulating factors that modulate phosphate metabolism including fibroblast growth factor 23 (FGF23) and soluble Klotho. Reduced circulating levels and suppressed renal klotho expression may be associated with adverse outcomes in CKD patients. While elevated circulating concentrations or locally produced FGF23 in the strained heart exert pro-hypertrophic mechanisms on the myocardium, Klotho attenuates tissue fibrosis, progression of CKD, cardiomyopathy, endothelial dysfunction, vascular stiffness, and vascular calcification. Mineralocorticoid receptor (MR) activation in non-classical targets, mediated by aldosterone and other ligands, amplifies CVD in CKD. In concert, we detail how the interplay of elevated FGF23, activation of the MR, and concomitant reductions of circulating Klotho in CKD, may potentiate each other's deleterious effects on kidney and the heart, thereby contributing to the initiation and progression of kidney and cardiac functional deterioration, acting through multipronged albeit complementary mechanistic pathways.
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Affiliation(s)
- Murray Epstein
- Division of Nephrology and Hypertension, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Michael Freundlich
- Division of Pediatric Nephrology, University of Miami Miller School of Medicine, Miami, FL, USA
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Inflammation: a putative link between phosphate metabolism and cardiovascular disease. Clin Sci (Lond) 2021; 135:201-227. [PMID: 33416083 PMCID: PMC7796315 DOI: 10.1042/cs20190895] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 02/06/2023]
Abstract
Dietary habits in the western world lead to increasing phosphate intake. Under physiological conditions, extraosseous precipitation of phosphate with calcium is prevented by a mineral buffering system composed of calcification inhibitors and tight control of serum phosphate levels. The coordinated hormonal regulation of serum phosphate involves fibroblast growth factor 23 (FGF23), αKlotho, parathyroid hormone (PTH) and calcitriol. A severe derangement of phosphate homeostasis is observed in patients with chronic kidney disease (CKD), a patient collective with extremely high risk of cardiovascular morbidity and mortality. Higher phosphate levels in serum have been associated with increased risk for cardiovascular disease (CVD) in CKD patients, but also in the general population. The causal connections between phosphate and CVD are currently incompletely understood. An assumed link between phosphate and cardiovascular risk is the development of medial vascular calcification, a process actively promoted and regulated by a complex mechanistic interplay involving activation of pro-inflammatory signalling. Emerging evidence indicates a link between disturbances in phosphate homeostasis and inflammation. The present review focuses on critical interactions of phosphate homeostasis, inflammation, vascular calcification and CVD. Especially, pro-inflammatory responses mediating hyperphosphatemia-related development of vascular calcification as well as FGF23 as a critical factor in the interplay between inflammation and cardiovascular alterations, beyond its phosphaturic effects, are addressed.
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23
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Tyurenkov IN, Perfilova VN, Nesterova AA, Glinka Y. Klotho Protein and Cardio-Vascular System. BIOCHEMISTRY (MOSCOW) 2021; 86:132-145. [PMID: 33832412 DOI: 10.1134/s0006297921020024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Klotho protein affects a number of metabolic pathways essential for pathogenesis of cardio-vascular diseases and their prevention. It inhibits lipid peroxidation and inflammation, as well as prevents endothelial injury and calcification of blood vessels. Klotho decreases rigidity of blood vessels and suppresses development of the heart fibrosis. Low level of its expression is associated with a number of diseases. Cardioprotective effect of klotho is based on its ability to interact with multiple receptors and ion channels. Being a pleiotropic protein, klotho could be a useful target for therapeutic intervention in the treatment of cardio-vascular diseases. In this review we present data on pharmaceuticals that stimulate klotho expression and suggest some promising research directions.
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Affiliation(s)
- Ivan N Tyurenkov
- Volgograd State Medical University, Ministry of Health of the Russian Federation, Volgograd, 400066, Russia
| | - Valentina N Perfilova
- Volgograd State Medical University, Ministry of Health of the Russian Federation, Volgograd, 400066, Russia.
| | - Alla A Nesterova
- Pyatigorsk Medical and Pharmaceutical Institute, Branch of the Volgograd State Medical University, Ministry of Health of the Russian Federation, Pyatigorsk, 357500, Russia
| | - Yelena Glinka
- Keenan Research Centre, St. Michael's Hospital, Toronto, ON M5B 1W8, Canada
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24
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Hanson K, Fisher K, Hooper N. Exploiting the neuroprotective effects of α-klotho to tackle ageing- and neurodegeneration-related cognitive dysfunction. Neuronal Signal 2021; 5:NS20200101. [PMID: 34194816 PMCID: PMC8204227 DOI: 10.1042/ns20200101] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/26/2022] Open
Abstract
Cognitive dysfunction is a key symptom of ageing and neurodegenerative disorders, such as Alzheimer's disease (AD). Strategies to enhance cognition would impact the quality of life for a significant proportion of the ageing population. The α-klotho protein may protect against cognitive decline through multiple mechanisms: such as promoting optimal synaptic function via activation of N-methyl-d-aspartate (NMDA) receptor signalling; stimulating the antioxidant defence system; reducing inflammation; promoting autophagy and enhancing clearance of amyloid-β. However, the molecular and cellular pathways by which α-klotho mediates these neuroprotective functions have yet to be fully elucidated. Key questions remain unanswered: which form of α-klotho (transmembrane, soluble or secreted) mediates its cognitive enhancing properties; what is the neuronal receptor for α-klotho and which signalling pathways are activated by α-klotho in the brain to enhance cognition; how does peripherally administered α-klotho mediate neuroprotection; and what is the molecular basis for the beneficial effect of the VS variant of α-klotho? In this review, we summarise the recent research on neuronal α-klotho and discuss how the neuroprotective properties of α-klotho could be exploited to tackle age- and neurodegeneration-associated cognitive dysfunction.
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Affiliation(s)
- Kelsey Hanson
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Kate Fisher
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Nigel M. Hooper
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance and University of Manchester, Manchester, U.K
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25
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The Complexity of FGF23 Effects on Cardiomyocytes in Normal and Uremic Milieu. Cells 2021; 10:cells10051266. [PMID: 34065339 PMCID: PMC8161087 DOI: 10.3390/cells10051266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 02/06/2023] Open
Abstract
Fibroblast growth factor-23 (FGF23) appears to be one of the most promising biomarkers and predictors of cardiovascular risk in patients with heart disease and normal kidney function, but moreover in those with chronic kidney disease (CKD). This review summarizes the current knowledge of FGF23 mechanisms of action in the myocardium in the physiological and pathophysiological state of CKD, as well as its cross-talk to other important signaling pathways in cardiomyocytes. In this regard, current therapeutic possibilities and future perspectives are also discussed.
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26
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Kawarazaki W, Fujita T. Kidney and epigenetic mechanisms of salt-sensitive hypertension. Nat Rev Nephrol 2021; 17:350-363. [PMID: 33627838 DOI: 10.1038/s41581-021-00399-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
Dietary salt intake increases blood pressure (BP) but the salt sensitivity of BP differs between individuals. The interplay of ageing, genetics and environmental factors, including malnutrition and stress, contributes to BP salt sensitivity. In adults, obesity is often associated with salt-sensitive hypertension. The children of women who experience malnutrition during pregnancy are at increased risk of developing obesity, diabetes and salt-sensitive hypertension as adults. Similarly, the offspring of mice that are fed a low-protein diet during pregnancy develop salt-sensitive hypertension in association with aberrant DNA methylation of the gene encoding type 1A angiotensin II receptor (AT1AR) in the hypothalamus, leading to upregulation of hypothalamic AT1AR and renal sympathetic overactivity. Ageing is also associated with salt-sensitive hypertension. In aged mice, promoter methylation leads to reduced kidney production of the anti-ageing factor Klotho and a decrease in circulating soluble Klotho. In the setting of Klotho deficiency, salt-induced activation of the vascular Wnt5a-RhoA pathway leads to ageing-associated salt-sensitive hypertension, potentially as a result of reduced renal blood flow and increased peripheral resistance. Thus, kidney mechanisms and aberrant DNA methylation of certain genes are involved in the development of salt-sensitive hypertension during fetal development and old age. Three distinct paradigms of epigenetic memory operate on different timescales in prenatal malnutrition, obesity and ageing.
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Affiliation(s)
- Wakako Kawarazaki
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan. .,School of Medicine, Shinshu University, Matsumoto, Japan. .,Research Center for Social Systems, Shinshu University, Matsumoto, Japan.
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27
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Bogdanova E, Beresneva O, Galkina O, Zubina I, Ivanova G, Parastaeva M, Semenova N, Dobronravov V. Myocardial Hypertrophy and Fibrosis Are Associated with Cardiomyocyte Beta-Catenin and TRPC6/Calcineurin/NFAT Signaling in Spontaneously Hypertensive Rats with 5/6 Nephrectomy. Int J Mol Sci 2021; 22:4645. [PMID: 33924991 PMCID: PMC8124394 DOI: 10.3390/ijms22094645] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Arterial hypertension (AH) is associated with heart and chronic kidney disease (CKD). However, the precise mechanisms of myocardial remodeling (MR) in the settings of CKD remain elusive. We hypothesized that TRPC6, calcineurin/NFAT, and Wnt/β-catenin signaling pathways are involved in the development of MR in the background of CKD and AH. METHODS Early CKD was induced by performing a 5/6 nephrectomy (5/6NE) in spontaneously hypertensive rats (SHR-NE). Sham-operated (SO) SHR (SHR-SO) and Wistar Kyoto (WKY-SO) rats served as controls. Systolic blood pressure (SBP), heart rate, myocardial mass index (MMI), serum creatinine, cardiomyocyte diameter (dCM), myocardial fibrosis (MF), serum and kidney α-Klotho levels, myocardial expression of calcineurin (CaN), TRPC6, and β-catenin were measured two months after 5/6NE or SO. RESULTS NE-induced kidney dysfunction corresponded to mild-to-moderate human CKD and was associated with an increase in FGF23 and a decrease in renal α-Klotho. The levels of SBP, MMI, dCM, and MF were higher in SHRs compared to WKY-SO as well as in SHR-NE vs. SHR-SO. The MR was associated with increased cardiomyocyte expression of CaN/NFAT and β-catenin along with its intracellular re-distribution. TRPC6 protein levels were substantially elevated in both SHR groups with higher Trpc6 mRNA expression in SHR-NE. CONCLUSIONS The Wnt/β-catenin and TRPC6/CaN/NFAT hypertrophic signaling pathways seem to be involved in myocardial remodeling in the settings of AH and CKD and might be mediated by FGF23 and α-Klotho axis.
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Affiliation(s)
- Evdokia Bogdanova
- Research Institute of Nephrology, Pavlov University, Saint Petersburg 197022, Russia; (E.B.); (O.B.); (O.G.); (I.Z.); (M.P.)
| | - Olga Beresneva
- Research Institute of Nephrology, Pavlov University, Saint Petersburg 197022, Russia; (E.B.); (O.B.); (O.G.); (I.Z.); (M.P.)
| | - Olga Galkina
- Research Institute of Nephrology, Pavlov University, Saint Petersburg 197022, Russia; (E.B.); (O.B.); (O.G.); (I.Z.); (M.P.)
| | - Irina Zubina
- Research Institute of Nephrology, Pavlov University, Saint Petersburg 197022, Russia; (E.B.); (O.B.); (O.G.); (I.Z.); (M.P.)
| | - Galina Ivanova
- Laboratory of Cardiovascular and Lymphatic Systems Physiology, Pavlov Institute of Physiology, Saint Petersburg 199034, Russia;
| | - Marina Parastaeva
- Research Institute of Nephrology, Pavlov University, Saint Petersburg 197022, Russia; (E.B.); (O.B.); (O.G.); (I.Z.); (M.P.)
| | - Natalia Semenova
- Research Department of Pathomorphology, Almazov National Medical Research Center, Saint Petersburg 197341, Russia;
- Laboratory of Leukemia Research, Russian Research Institute of Hematology and Transfusiology of FMBA of Russia, Saint Petersburg 191024, Russia
| | - Vladimir Dobronravov
- Research Institute of Nephrology, Pavlov University, Saint Petersburg 197022, Russia; (E.B.); (O.B.); (O.G.); (I.Z.); (M.P.)
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28
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Hu PP, Bao JF, Li A. Roles for fibroblast growth factor-23 and α-Klotho in acute kidney injury. Metabolism 2021; 116:154435. [PMID: 33220250 DOI: 10.1016/j.metabol.2020.154435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/08/2020] [Accepted: 11/13/2020] [Indexed: 12/21/2022]
Abstract
Acute kidney injury is a global disease with high morbidity and mortality. Recent studies have revealed that the fibroblast growth factor-23-α-Klotho axis is closely related to chronic kidney disease, and has multiple biological functions beyond bone-mineral metabolism. However, although dysregulation of fibroblast growth factor-23-α-Klotho has been observed in acute kidney injury, the role of fibroblast growth factor-23-α-Klotho in the pathophysiology of acute kidney injury remains largely unknown. In this review, we describe recent findings regarding fibroblast growth factor-23-α-Klotho, which is mainly involved in inflammation, oxidative stress, and hemodynamic disorders. Further, based on these recent results, we put forth novel insights regarding the relationship between the fibroblast growth factor-23-α-Klotho axis and acute kidney injury, which may provide new therapeutic targets for treating acute kidney injury.
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Affiliation(s)
- Pan-Pan Hu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, 510515 Guangzhou, China; Guangdong Provincial Key Laboratory of Renal Failure Research, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005 Guangzhou, China
| | - Jing-Fu Bao
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, 510515 Guangzhou, China; Guangdong Provincial Key Laboratory of Renal Failure Research, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005 Guangzhou, China
| | - Aiqing Li
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, 510515 Guangzhou, China; Guangdong Provincial Key Laboratory of Renal Failure Research, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005 Guangzhou, China.
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29
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Lee J, Ju KD, Kim HJ, Tsogbadrakh B, Ryu H, Kang E, Kang M, Yang J, Kang HG, Ahn C, Oh KH. Soluble α-klotho anchors TRPV5 to the distal tubular cell membrane independent of FGFR1 by binding TRPV5 and galectin-1 simultaneously. Am J Physiol Renal Physiol 2021; 320:F559-F568. [PMID: 33615893 DOI: 10.1152/ajprenal.00044.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hypercalciuria is one of the early manifestations of diabetic nephropathy (DN). This is partially due to a decrease in the expression of renal transient receptor potential vanilloid type 5 (TRPV5), which is responsible for renal Ca2+ reabsorption. Soluble klotho has been previously determined to increase TRPV5 by cleaving sialic acid, causing TRPV5 to bind to membrane protein galectin-1. However, a recent study showed that soluble klotho binds to α2-3-sialyllactose, where sialic acid is located, on TRPV5, rather than cleave it. Here, we report that soluble klotho tethers TRPV5 on the membrane by binding both TRPV5 and galectin-1, thereby protecting membrane TRPV5 from diabetes-induced endocytosis. In the present study, we injected recombinant soluble α-klotho protein (rKL) into db/db and db/m mice for 8 wk and collected urine and kidneys. We administered rKL, AZD4547 [fibroblast growth factor (FGF) receptor type 1 inhibitor], and OTX008 (galectin-1 inhibitor) to cultured mouse distal tubular cells with or without 30 mM high-glucose (HG) exposure. db/db mice showed increased renal Ca2+ excretion and decreased renal TRPV5 expression. rKL treatment reversed this change. In vitro, TRPV5 expression in distal tubular cells decreased under HG conditions, and rKL successfully upregulated TRPV5 with or without FGF23. Also, immunofluorescence showed colocalization of klotho, TRPV5, and galectin-1 in distal tubule cells, suggesting that klotho binds to both TRPV5 and galectin-1. Moreover, when both FGF receptor type 1 and galectin-1 were inhibited, rKL failed to increase TRPV5 under HG conditions. Our results indicate that soluble klotho prevents TRPV5 from degradation and subsequent diabetes-induced endocytosis by anchoring TRPV5 through binding with both TRPV5 and galectin-1.NEW & NOTEWORTHY Soluble α-klotho anchors transient receptor potential vanilloid type 5 (TRPV5) on the apical membrane of the distal tubule by binding both TRPV5 and a membrane-abundant protein, galectin-1. This newly discovered mechanism works even when fibroblast growth factor (FGF)23 signaling is inhibited by treatment with FGF receptor type 1 inhibitor. Therefore, we identified how soluble α-klotho increases TRPV5 without FGF23. We confirmed this mechanism by observing that soluble α-klotho fails to enhance TRPV5 when both FGF receptor type 1 and galectin-1 are inhibited.
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Affiliation(s)
- Jinho Lee
- Center of Medical Innovation, Seoul National University Hospital, Seoul, Korea
| | - Kyung Don Ju
- Center of Medical Innovation, Seoul National University Hospital, Seoul, Korea
| | - Hyo Jin Kim
- Department of Internal Medicine, Pusan National University Hospital, Busan, Korea
| | | | - Hyunjin Ryu
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Eunjeong Kang
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Minjung Kang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jaeseok Yang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.,Transplantation Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.,Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea.,Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Curie Ahn
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.,Transplantation Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
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30
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Saar-Kovrov V, Donners MMPC, van der Vorst EPC. Shedding of Klotho: Functional Implications in Chronic Kidney Disease and Associated Vascular Disease. Front Cardiovasc Med 2021; 7:617842. [PMID: 33585584 PMCID: PMC7876272 DOI: 10.3389/fcvm.2020.617842] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
α-Klotho (Klotho) exists in two different forms, a membrane-bound and soluble form, which are highly expressed in the kidney. Both forms play an important role in various physiological and pathophysiological processes. Recently, it has been identified that soluble Klotho arises exclusively from shedding or proteolytic cleavage. In this review, we will highlight the mechanisms underlying the shedding of Klotho and the functional effects of soluble Klotho, especially in CKD and the associated cardiovascular complications. Klotho can be cleaved by a process called shedding, releasing the ectodomain of the transmembrane protein. A disintegrin and metalloproteases ADAM10 and ADAM17 have been demonstrated to be mainly responsible for this shedding, resulting in either full-length fragments or sub-fragments called KL1 and KL2. Reduced levels of soluble Klotho have been associated with kidney disease, especially chronic kidney disease (CKD). In line with a protective effect of soluble Klotho in vascular function and calcification, CKD and the reduced levels of soluble Klotho herein are associated with cardiovascular complications. Interestingly, although it has been demonstrated that soluble Klotho has a multitude of effects its direct impact on vascular cells and the exact underlying mechanisms remain largely unknown and should therefore be a major focus of further research. Moreover, functional implications of the cleavage process resulting in KL1 and KL2 fragments remain to be elucidated.
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Affiliation(s)
- Valeria Saar-Kovrov
- Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands.,Institute for Molecular Cardiovascular Research, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany
| | - Marjo M P C Donners
- Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Emiel P C van der Vorst
- Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands.,Institute for Molecular Cardiovascular Research, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany.,Interdisciplinary Centre for Clinical Research, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany.,Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany.,German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany
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31
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Kim JH, Park EY, Hwang KH, Park KS, Choi SJ, Cha SK. Soluble αKlotho downregulates Orai1-mediated store-operated Ca 2+ entry via PI3K-dependent signaling. Pflugers Arch 2021; 473:647-658. [PMID: 33386992 PMCID: PMC8049930 DOI: 10.1007/s00424-020-02510-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/20/2020] [Accepted: 12/23/2020] [Indexed: 12/17/2022]
Abstract
αKlotho is a type 1 transmembrane anti-aging protein. αKlotho-deficient mice have premature aging phenotypes and an imbalance of ion homeostasis including Ca2+ and phosphate. Soluble αKlotho is known to regulate multiple ion channels and growth factor-mediated phosphoinositide-3-kinase (PI3K) signaling. Store-operated Ca2+ entry (SOCE) mediated by pore-forming subunit Orai1 and ER Ca2+ sensor STIM1 is a ubiquitous Ca2+ influx mechanism and has been implicated in multiple diseases. However, it is currently unknown whether soluble αKlotho regulates Orai1-mediated SOCE via PI3K-dependent signaling. Among the Klotho family, αKlotho downregulates SOCE while βKlotho or γKlotho does not affect SOCE. Soluble αKlotho suppresses serum-stimulated SOCE and Ca2+ release-activated Ca2+ (CRAC) channel currents. Serum increases the cell-surface abundance of Orai1 via stimulating vesicular exocytosis of the channel. The serum-stimulated SOCE and cell-surface abundance of Orai1 are inhibited by the preincubation of αKlotho protein or PI3K inhibitors. Moreover, the inhibition of SOCE and cell-surface abundance of Orai1 by pretreatment of brefeldin A or tetanus toxin or PI3K inhibitors prevents further inhibition by αKlotho. Functionally, we further show that soluble αKlotho ameliorates serum-stimulated SOCE and cell migration in breast and lung cancer cells. These results demonstrate that soluble αKlotho downregulates SOCE by inhibiting PI3K-driven vesicular exocytosis of the Orai1 channel and contributes to the suppression of SOCE-mediated tumor cell migration.
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Affiliation(s)
- Ji-Hee Kim
- Department of Physiology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwondo, 26426, Republic of Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Institute of Mitochondrial Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Eun Young Park
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Department of Obstetrics and Gynecology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwondo, 26426, Republic of Korea
| | - Kyu-Hee Hwang
- Department of Physiology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwondo, 26426, Republic of Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Institute of Mitochondrial Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Kyu-Sang Park
- Department of Physiology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwondo, 26426, Republic of Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
- Institute of Mitochondrial Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Seong Jin Choi
- Department of Obstetrics and Gynecology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwondo, 26426, Republic of Korea.
| | - Seung-Kuy Cha
- Department of Physiology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwondo, 26426, Republic of Korea.
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.
- Institute of Mitochondrial Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.
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32
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Li J, Yuan J, Wang H, Zhang H, Zhang H. Arabidopsis COPPER TRANSPORTER 1 undergoes degradation in a proteasome-dependent manner. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6174-6186. [PMID: 32720982 DOI: 10.1093/jxb/eraa352] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
The essential nutrient copper is toxic in excess. Therefore, plants must tightly control copper uptake and distribution. Arabidopsis thaliana high-affinity copper transporters (COPTs) mediate copper uptake, partitioning, and redistribution. Here we show that COPT1 localizes to the plasma membrane and endoplasmic reticulum in stably transgenic plants expressing a COPT1-green fluorescent protein (GFP) fusion protein, and the fusion protein is rapidly degraded upon plant exposure to excess copper. MG132 treatment largely abolished copper-induced degradation of COPT1, implying a link between the proteasome and COPT1 activity in modulating copper uptake. Co-immunoprecipitation analyses revealed that COPT1 cannot be ubiquitinated in the presence of excess copper and MG132. Through site-directed mutagenesis, we identified Lys159 in the C-terminal cytoplasmic tail of COPT1 as critical for copper acquisition, but not for copper-mediated down-regulation of COPT1, in plants. Furthermore, pharmacological analysis showed that treatment with a vesicle trafficking inhibitor or a V-ATPase inhibitor does not alter the subcellular dynamics of COPT1-GFP, consistent with the absence of a connection between the endosomal recycling/vacuolar system and COPT1 degradation. Together, our data suggest that proteasomal degradation rather than vacuolar proteolysis is important for the regulation of copper transport to maintain copper homeostasis in plants.
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Affiliation(s)
- Jinjin Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jinhong Yuan
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Hui Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China
| | - Hui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Haiyan Zhang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China
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33
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Sipione S, Monyror J, Galleguillos D, Steinberg N, Kadam V. Gangliosides in the Brain: Physiology, Pathophysiology and Therapeutic Applications. Front Neurosci 2020; 14:572965. [PMID: 33117120 PMCID: PMC7574889 DOI: 10.3389/fnins.2020.572965] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Gangliosides are glycosphingolipids highly abundant in the nervous system, and carry most of the sialic acid residues in the brain. Gangliosides are enriched in cell membrane microdomains ("lipid rafts") and play important roles in the modulation of membrane proteins and ion channels, in cell signaling and in the communication among cells. The importance of gangliosides in the brain is highlighted by the fact that loss of function mutations in ganglioside biosynthetic enzymes result in severe neurodegenerative disorders, often characterized by very early or childhood onset. In addition, changes in the ganglioside profile (i.e., in the relative abundance of specific gangliosides) were reported in healthy aging and in common neurological conditions, including Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), stroke, multiple sclerosis and epilepsy. At least in HD, PD and in some forms of epilepsy, experimental evidence strongly suggests a potential role of gangliosides in disease pathogenesis and potential treatment. In this review, we will summarize ganglioside functions that are crucial to maintain brain health, we will review changes in ganglioside levels that occur in major neurological conditions and we will discuss their contribution to cellular dysfunctions and disease pathogenesis. Finally, we will review evidence of the beneficial roles exerted by gangliosides, GM1 in particular, in disease models and in clinical trials.
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Affiliation(s)
- Simonetta Sipione
- Department of Pharmacology, Faculty of Medicine and Dentistry, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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Bi X, Yang K, Zhang B, Zhao J. The Protective Role of Klotho in CKD-Associated Cardiovascular Disease. KIDNEY DISEASES 2020; 6:395-406. [PMID: 33313060 DOI: 10.1159/000509369] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 12/20/2022]
Abstract
Background Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in advanced CKD. The major pathological changes of CKD-associated CVD are severe vascular media calcification, aberrant cardiac remodeling such as hypertrophy and fibrosis, as well as accelerated atherosclerosis. α-Klotho is proposed as an anti-aging gene, which is primarily expressed in the kidney. Recent studies reveal that α-Klotho deficiency is associated with profound cardiovascular dysfunction. Of note, CKD represents extremely declined α-Klotho levels, hinting that α-Klotho deficiency may be implicated in the pathogenesis of CKD-associated CVD. Summary Based on the pathogenic mechanism of α-Klotho deficiency and decreased Klotho levels in the circulation even early in stage 1 of CKD, α-Klotho serves as a sensitive biomarker for renal insufficiency and also a novel predictor of risk of overall mortality of CVD events in CKD. Meanwhile, loss of Klotho resulted from kidney dysfunction markedly contributes to the progressive development of CKD and CVD. By contrast, prevention of Klotho decline using exogenous supplementation or genetically activated ways by several mechanisms can dramatically mitigate cardiac dysfunction, prevent vascular calcification, and retard the progression of CKD-accelerated atherosclerosis. Key Messages Klotho deficiency is proposed as a novel predictive biomarker as well as a pathogenic contributor to CVD events in CKD. In the future, Klotho may be a crucial potential therapeutic strategy to decrease the burden of CVD comorbidity with CKD in clinics.
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Affiliation(s)
- Xianjin Bi
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Kidney Center of PLA, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Ke Yang
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Kidney Center of PLA, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Bo Zhang
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Kidney Center of PLA, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jinghong Zhao
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Kidney Center of PLA, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
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Bao JF, Hu PP, She QY, Li A. A Land of Controversy: Fibroblast Growth Factor-23 and Uremic Cardiac Hypertrophy. J Am Soc Nephrol 2020; 31:1423-1434. [PMID: 32527977 PMCID: PMC7351013 DOI: 10.1681/asn.2020010081] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cardiac hypertrophy is a common feature in patients with CKD. Recent studies revealed that two phosphate regulators, fibroblast growth factor-23 and α-Klotho, are highly involved in the pathophysiologic process of CKD-induced cardiac hypertrophy. With decreasing renal function, elevated fibroblast growth factor-23 and decreased α-Klotho may contribute to cardiac hypertrophy by targeting the heart directly or by inducing systemic changes, such as vascular injury, hemodynamic disorders, and inflammation. However, several studies have demonstrated that disturbances in the fibroblast growth factor-23/α-Klotho axis do not lead to cardiac hypertrophy. In this review, we describe the cardiac effects of the fibroblast growth factor-23/α-Klotho axis and summarize recent progress in this field. In addition, we present not only the main controversies in this field but also provide possible directions to resolve these disputes.
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Affiliation(s)
- Jing-Fu Bao
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Pan-Pan Hu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qin-Ying She
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Aiqing Li
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, Guangzhou, China
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Tao J, Yu X, Guo Y, Wang G, Ju H, Ding L. Proximity Enzymatic Glyco-Remodeling Enables Direct and Highly Efficient Lipid Raft Imaging on Live Cells. Anal Chem 2020; 92:7232-7239. [PMID: 32297503 DOI: 10.1021/acs.analchem.0c00810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lipid rafts, highly ordered cell membrane domains mainly composed of cholesterol, sphingolipids, and protein receptors, serve as important functional platforms for regulation of lipid/protein interactions. The major predicament in lipid raft study is the lack of direct and robust visualization tools for in situ tracking raft components. To solve this issue, we herein report a proximity enzymatic glyco-remodeling strategy for direct and highly efficient lipid raft labeling and imaging on live cells. Through cofunctionalization of raft-specific recognition motif and glycan-remodeling enzyme on gold nanoparticles, the fabricated nanoprobe can be specifically guided to the raft domains to perform catalytic remodeling on neighboring glycans. Taking advantage of the abundant glycoconjugates enriched in lipid rafts, this elaborate design achieves the translation of one raft-recognition event to multiple raft-confined labeling operations, thus, significantly increasing the labeling efficiency and imaging sensitivity. The direct covalent labeling also enables in situ and long-term tracking of raft components in live cells. The method possesses broad applicability and potential expansibility, thus, will greatly facilitate the investigations on the complex composition, organization, and dynamics of lipid rafts.
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Affiliation(s)
- Jing Tao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, People's Republic of China
| | - Xiaofei Yu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, People's Republic of China
| | - Yuna Guo
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, People's Republic of China
| | - Guyu Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, People's Republic of China
| | - Huangxian Ju
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, People's Republic of China
| | - Lin Ding
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, People's Republic of China
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Dhayat NA, Pruijm M, Ponte B, Ackermann D, Leichtle AB, Devuyst O, Ehret G, Guessous I, Pechère-Bertschi A, Pastor J, Martin PY, Burnier M, Fiedler GM, Vogt B, Moe OW, Bochud M, Fuster DG. Parathyroid Hormone and Plasma Phosphate Are Predictors of Soluble α-Klotho Levels in Adults of European Descent. J Clin Endocrinol Metab 2020; 105:5644279. [PMID: 31774122 PMCID: PMC7341480 DOI: 10.1210/clinem/dgz232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/26/2019] [Indexed: 01/08/2023]
Abstract
CONTEXT α-klotho is an integral membrane protein that serves as a coreceptor for fibroblast growth factor 23 (FGF23) in conjunction with cognate fibroblast growth factor receptors. Proteolytic cleavage sheds the ectodomain of α-klotho (soluble α-klotho) as an endocrine substance into blood, urine, and cerebrospinal fluid. OBJECTIVE To study the relationship of soluble α-klotho to mineral metabolism in the general population with mainly preserved kidney function. DESIGN Cross-sectional analysis of the associations between soluble α-klotho with laboratory markers of markers of mineral metabolism in a population-based cohort. SETTING Three centers in Switzerland including 1128 participants. MEASURES Soluble full-length α-klotho levels by a specific immunoassay and markers of mineral metabolism. RESULTS The median serum level of soluble α-klotho was 15.0 pmol/L. Multivariable analyses using α-klotho as the outcome variable revealed a sex-by-PTH interaction: In men, PTH was positively associated with α-klotho levels, whereas this association was negative in women. Plasma phosphate associated with soluble α-klotho levels in an age-dependent manner, changing from a positive association in young adults gradually to a negative association in the elderly. The decline of 1,25 (OH)2 vitamin D3 levels in parallel to the gradual impairment of kidney function was greatly attenuated in the setting of high circulating soluble α-klotho levels. CONCLUSIONS Soluble α-klotho level is associated with plasma phosphate in an age-dependent manner and with PTH in a sex-dependent manner. Furthermore, our data reveal soluble α-klotho as a modulator of 1,25 (OH)2 vitamin D3 levels in individuals with preserved renal function.
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Affiliation(s)
- Nasser A Dhayat
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Menno Pruijm
- Nephrology Service, Lausanne University Hospital, Lausanne, Switzerland
| | - Belen Ponte
- Nephrology Service, Department of Specialties of Internal Medicine, Geneva University Hospital, Geneva, Switzerland
| | - Daniel Ackermann
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Alexander Benedikt Leichtle
- Department of Laboratory Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Insel Data Science Center, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Georg Ehret
- Cardiology Service, Department of Specialties of Internal Medicine, Geneva University Hospital, Geneva, Switzerland
| | - Idris Guessous
- Division of Primary Care Medicine, Geneva University Hospital, Geneva, Switzerland
| | - Antoinette Pechère-Bertschi
- Endocrinology Service, Department of Specialties of Internal Medicine, Geneva University Hospital, Geneva, Switzerland
| | - Johanne Pastor
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, Department of Physiology and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Pierre-Yves Martin
- Nephrology Service, Department of Specialties of Internal Medicine, Geneva University Hospital, Geneva, Switzerland
| | - Michel Burnier
- Nephrology Service, Lausanne University Hospital, Lausanne, Switzerland
| | - Georg-Martin Fiedler
- Department of Laboratory Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Bruno Vogt
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Orson W Moe
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, Department of Physiology and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Murielle Bochud
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland
| | - Daniel G Fuster
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Correspondence and Reprint Requests: Daniel G. Fuster, Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 15, 3010 Bern, Switzerland. E-mail:
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Munc13 mediates klotho-inhibitable diacylglycerol-stimulated exocytotic insertion of pre-docked TRPC6 vesicles. PLoS One 2020; 15:e0229799. [PMID: 32134975 PMCID: PMC7058344 DOI: 10.1371/journal.pone.0229799] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/13/2020] [Indexed: 11/29/2022] Open
Abstract
α-Klotho is a type 1 transmembrane protein that exhibits aging suppression function. The large amino-terminal extracellular domain of α-klotho is shed as soluble klotho (sKlotho) and functions as a circulating cardioprotective hormone. Diacylglycerol (DAG)-activated calcium-permeable TRPC6 channel plays a critical role in stress-induced cardiac remodeling. DAG activates TRPC6 by acting directly on the channel to increase its activity and by stimulation of channel exocytosis. sKlotho protects the heart by inhibiting DAG stimulation of TRPC6 exocytosis. How DAG stimulates TRPC6 exocytosis and thereby inhibition by sKlotho are unknown. Using a compound that directly activates TRPC6 without affecting channel exocytosis, we validate that sKlotho selectively blocks DAG stimulation of channel exocytosis. We further show that DAG stimulates exocytosis of TRPC6-containing vesicles pre-docked to the plasma membrane. Mnuc13 family proteins play important roles in the proper assembly of SNARE proteins and priming the vesicle competent for fusion. We show that DAG stimulates TRPC6 exocytosis by targeting to the C1 domain of Munc13-2. The results provide fresh insights into the molecular mechanism by which DAG regulates vesicle fusion and how sKlotho protects the heart against injury.
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Garth J, Easter M, Skylar Harris E, Sailland J, Kuenzi L, Chung S, Dennis JS, Baumlin N, Adewale AT, Rowe SM, King G, Faul C, Barnes JW, Salathe M, Krick S. The Effects of the Anti-aging Protein Klotho on Mucociliary Clearance. Front Med (Lausanne) 2020; 6:339. [PMID: 32039219 PMCID: PMC6992571 DOI: 10.3389/fmed.2019.00339] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/24/2019] [Indexed: 01/23/2023] Open
Abstract
α-klotho (KL) is an anti-aging protein and has been shown to exert anti-inflammatory and anti-oxidative effects in the lung and pulmonary diseases such as chronic obstructive pulmonary disease (COPD) and cystic fibrosis. The current study investigated the direct effect of KL on the bronchial epithelium in regards to mucociliary clearance parameters. Primary human bronchial and murine tracheal epithelial cells, cultured, and differentiated at the air liquid interface (ALI), were treated with recombinant KL or infected with a lentiviral vector expressing KL. Airway surface liquid (ASL) volume, airway ion channel activities, and expression levels were analyzed. These experiments were paired with ex vivo analyses of mucociliary clearance in murine tracheas from klotho deficient mice and their wild type littermates. Our results showed that klotho deficiency led to impaired mucociliary clearance with a reduction in ASL volume in vitro and ex vivo. Overexpression or exogenous KL increased ASL volume, which was paralleled by increased activation of the large-conductance, Ca2+-activated, voltage-dependent potassium channel (BK) without effect on the cystic fibrosis transmembrane conductance regulator (CFTR). Furthermore, KL overexpression downregulated IL-8 levels and attenuated TGF-β-mediated downregulation of LRRC26, the γ subunit of BK, necessary for its function in non-excitable cells. In summary, we show that KL regulates mucociliary function by increasing ASL volume in the airways possibly due to underlying BK activation. The KL mediated BK channel activation may be a potentially important target to design therapeutic strategies in inflammatory airway diseases when ASL volume is decreased.
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Affiliation(s)
- Jaleesa Garth
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Molly Easter
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Elex Skylar Harris
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Juliette Sailland
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Lisa Kuenzi
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Samuel Chung
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine University of Kansas Medical Center, Kansas City, KS, United States
| | - John S. Dennis
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine University of Kansas Medical Center, Kansas City, KS, United States
| | - Nathalie Baumlin
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine University of Kansas Medical Center, Kansas City, KS, United States
| | - Adegboyega T. Adewale
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine University of Kansas Medical Center, Kansas City, KS, United States
| | - Steven M. Rowe
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Gwendalyn King
- Department of Biology, Creighton University, Omaha, NE, United States
| | - Christian Faul
- Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jarrod W. Barnes
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Matthias Salathe
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine University of Kansas Medical Center, Kansas City, KS, United States
| | - Stefanie Krick
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, United States
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Han X, Cai C, Xiao Z, Quarles LD. FGF23 induced left ventricular hypertrophy mediated by FGFR4 signaling in the myocardium is attenuated by soluble Klotho in mice. J Mol Cell Cardiol 2020; 138:66-74. [PMID: 31758962 PMCID: PMC7195870 DOI: 10.1016/j.yjmcc.2019.11.149] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/12/2019] [Accepted: 11/14/2019] [Indexed: 12/15/2022]
Abstract
There is controversy regarding whether excess FGF23 causes left ventricular hypertrophy (LVH) directly through activation of fibroblast growth factor receptor 4 (FGFR4) in cardiomyocytes or indirectly through reductions in soluble Klotho (sK). We investigated the respective roles of myocardial FGFR4 and sKL in mediating FGF23-induced LVH using mouse genetic and pharmacological approaches. To investigate a direct role of myocardial FGFR4 in mediating the cardiotoxic effects of excess circulating FGF23, we administered rFGF23 to mice with cardiac-specific loss of FGFR4 (FGFR4 heart-cKO). We tested a model of sKL deficiency, hypertension and LVH created by the conditional deletion of FGFR1 in the renal distal tubule (FGFR1DT cKO mice). The cardioprotective effects of sKL in both mouse models was assessed by the systemic administration of recombinant sKL. We confirmed that FGF23 treatment activates PLCγ in the heart and induces LVH in the absence of membrane α-Klotho. Conditional deletion of FGFR4 in the myocardium prevented rFGF23-induced LVH in mice, establishing direct cardiotoxicity of FGF23 through activation of FGFR4. Recombinant sKL administration prevented LVH, but not HTN, in FGFR1DT cKO mice, consistent with direct cardioprotective effects. Co-administration of recombinant sKL with FGF23 in culture inhibited rFGF23-induced p-PLCγ signaling. Thus, FGF23 ability to include LVH represents a balance between FGF23 direct cardiac activation of FGFR4 and the modulating effects of circulating sKL to alter FGF23-dependent myocardial signaling pathways.
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Affiliation(s)
- Xiaobin Han
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, United States of America
| | - Chun Cai
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, United States of America
| | - Zhousheng Xiao
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, United States of America
| | - L Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, United States of America.
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Suassuna PGDA, Cherem PM, de Castro BB, Maquigussa E, Cenedeze MA, Lovisi JCM, Custódio MR, Sanders-Pinheiro H, de Paula RB. αKlotho attenuates cardiac hypertrophy and increases myocardial fibroblast growth factor 21 expression in uremic rats. Exp Biol Med (Maywood) 2019; 245:66-78. [PMID: 31847589 DOI: 10.1177/1535370219894302] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In chronic kidney disease (CKD), evidence suggests that soluble αKlotho (sKlotho) has cardioprotective effects. Contrariwise, high circulating levels of fibroblast growth factor 23 (FGF23) are related to uremic cardiomyopathy development. Recently, it has been demonstrated that sKlotho can act as a soluble FGF23 co-receptor, allowing sKlotho to modulate FGF23 actions in the myocardium, leading to the activation of cardioprotective pathways. Fibroblast growth factor 21 (FGF21) is a cardiomyokine with sKlotho-like protective actions and has never been evaluated in uremic cardiomyopathy. Here, we aimed to evaluate whether recombinant αKlotho (rKlotho) replacement can attenuate cardiac remodeling in an established uremic cardiomyopathy, and to explore its impact on myocardial FGF21 expression. Forty-six male Wistar rats were divided into three groups: control, CKD-untreated, and CKD treated with rKlotho (CKD + KL). CKD was induced by 5/6 nephrectomy. From weeks 4–8, the control and CKD-untreated groups received vehicle, whereas the CKD + KL group received subcutaneous rKlotho replacement (0.01 mg/kg) every 48 h. Myocardial remodeling was evaluated by heart weight/tibia length (HW/TL) ratio, echocardiographic parameters, myocardial histomorphometry, and myocardial expression of β-myosin heavy chain (MHCβ), alpha smooth muscle actin (αSMA), transient receptor potential cation channel 6 (TRPC6), and FGF21. As expected, CKD animals had reduced levels of sKlotho and increased serum FGF23 levels. Compared to the control group, manifest myocardial remodeling was present in the CKD-untreated group, while it was attenuated in the CKD + KL group. Furthermore, cardiomyocyte diameter and interstitial fibrotic area were reduced in the CKD + KL group compared to the CKD-untreated group. Similarly, rKlotho replacement was associated with reduced myocardial expression of TRPC6, MHCβ, and αSMA and a higher expression of FGF21. rKlotho showed cardioprotective effects by attenuating myocardial remodeling and reducing TRPC6 expression. Interestingly, rKlotho replacement was also associated with increased myocardial FGF21 expression, suggesting that an interaction between the two cardioprotective pathways needs to be further explored. Impact statement This study aimed to evaluate whether rKlotho replacement can attenuate cardiac remodeling in a post-disease onset therapeutic reasoning and explore the impact on myocardial FGF21 expression. This study contributes significantly to the literature, as the therapeutic effects of rKlotho replacement and FGF21 myocardial expression have not been widely evaluated in a setting of uremic cardiomyopathy. For the first time, it has been demonstrated that subcutaneous rKlotho replacement may attenuate cardiac remodeling in established uremic cardiomyopathy and increase myocardial expression of FGF21, suggesting a correlation between αKlotho and myocardial FGF21 expression. The possibility of interaction between the αKlotho and FGF21 cardioprotective pathways needs to be further explored, but, if confirmed, would point to a therapeutic potential of FGF21 in uremic cardiomyopathy.
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Affiliation(s)
- Paulo Giovani de Albuquerque Suassuna
- Laboratory of Experimental Nephrology (LABNEX) and Interdisciplinary Nucleus of Laboratory Animal Studies (NIDEAL), Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais 36036-900, Brazil.,Interdisciplinary Center for Studies, Research and Treatment in Nephrology (NIEPEN), Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Paula Marocolo Cherem
- Laboratory of Experimental Nephrology (LABNEX) and Interdisciplinary Nucleus of Laboratory Animal Studies (NIDEAL), Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Bárbara Bruna de Castro
- Laboratory of Experimental Nephrology (LABNEX) and Interdisciplinary Nucleus of Laboratory Animal Studies (NIDEAL), Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Edgar Maquigussa
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo 04024-002, Brazil
| | - Marco Antonio Cenedeze
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo 04024-002, Brazil
| | - Júlio Cesar Moraes Lovisi
- Interdisciplinary Center for Studies, Research and Treatment in Nephrology (NIEPEN), Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Melani Ribeiro Custódio
- Nephrology Division, Department of Medicine, University of São Paulo, São Paulo 01246-903, Brazil
| | - Helady Sanders-Pinheiro
- Laboratory of Experimental Nephrology (LABNEX) and Interdisciplinary Nucleus of Laboratory Animal Studies (NIDEAL), Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais 36036-900, Brazil.,Interdisciplinary Center for Studies, Research and Treatment in Nephrology (NIEPEN), Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Rogério Baumgratz de Paula
- Laboratory of Experimental Nephrology (LABNEX) and Interdisciplinary Nucleus of Laboratory Animal Studies (NIDEAL), Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais 36036-900, Brazil.,Interdisciplinary Center for Studies, Research and Treatment in Nephrology (NIEPEN), Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais 36036-900, Brazil
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Smith ER, Holt SG, Hewitson TD. αKlotho-FGF23 interactions and their role in kidney disease: a molecular insight. Cell Mol Life Sci 2019; 76:4705-4724. [PMID: 31350618 PMCID: PMC11105488 DOI: 10.1007/s00018-019-03241-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 07/09/2019] [Accepted: 07/22/2019] [Indexed: 12/16/2022]
Abstract
Following the serendipitous discovery of the ageing suppressor, αKlotho (αKl), several decades ago, a growing body of evidence has defined a pivotal role for its various forms in multiple aspects of vertebrate physiology and pathology. The transmembrane form of αKl serves as a co-receptor for the osteocyte-derived mineral regulator, fibroblast growth factor (FGF)23, principally in the renal tubules. However, compelling data also suggest that circulating soluble forms of αKl, derived from the same source, may have independent homeostatic functions either as a hormone, glycan-cleaving enzyme or lectin. Chronic kidney disease (CKD) is of particular interest as disruption of the FGF23-αKl axis is an early and common feature of disease manifesting in markedly deficient αKl expression, but FGF23 excess. Here we critically discuss recent findings in αKl biology that conflict with the view that soluble αKl has substantive functions independent of FGF23 signalling. Although the issue of whether soluble αKl can act without FGF23 has yet to be resolved, we explore the potential significance of these contrary findings in the context of CKD and highlight how this endocrine pathway represents a promising target for novel anti-ageing therapeutics.
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Affiliation(s)
- Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Australia.
- Department of Medicine, University of Melbourne, Grattan Street, Parkville, VIC, 3050, Australia.
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Australia
- Department of Medicine, University of Melbourne, Grattan Street, Parkville, VIC, 3050, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Australia
- Department of Medicine, University of Melbourne, Grattan Street, Parkville, VIC, 3050, Australia
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Fibroblast growth factor 23 and α-Klotho co-dependent and independent functions. Curr Opin Nephrol Hypertens 2019; 28:16-25. [PMID: 30451736 DOI: 10.1097/mnh.0000000000000467] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE OF REVIEW The current review examines what is known about the FGF-23/α-Klotho co-dependent and independent pathophysiological effects, and whether FGF-23 and/or α-Klotho are potential therapeutic targets. RECENT FINDINGS FGF-23 is a hormone derived mainly from bone, and α-Klotho is a transmembrane protein. Together they form a trimeric signaling complex with FGFRs in target tissues to mediate the physiological functions of FGF-23. Local and systemic factors control FGF-23 release from osteoblast/osteocytes in bone, and circulating FGF-23 activates FGFR/α-Klotho complexes in kidney proximal and distal renal tubules to regulate renal phosphate excretion, 1,25 (OH)2D metabolism, sodium and calcium reabsorption, and ACE2 and α-Klotho expression. The resulting bone-renal-cardiac-immune networks provide a new understanding of bone and mineral homeostasis, as well as identify other biological effects FGF-23. Direct FGF-23 activation of FGFRs in the absence of α-Klotho is proposed to mediate cardiotoxic and adverse innate immune effects of excess FGF-23, particularly in chronic kidney disease, but this FGF-23, α-Klotho-independent signaling is controversial. In addition, circulating soluble Klotho (sKl) released from the distal tubule by ectodomain shedding is proposed to have beneficial health effects independent of FGF-23. SUMMARY Separation of FGF-23 and α-Klotho independent functions has been difficult in mammalian systems and understanding FGF-23/α-Klotho co-dependent and independent effects are incomplete. Antagonism of FGF-23 is important in treatment of hypophosphatemic disorders caused by excess FGF-23, but its role in chronic kidney disease is uncertain. Administration of recombinant sKl is an unproven therapeutic strategy that theoretically could improve the healt span and lifespan of patients with α-Klotho deficiency.
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Barnes JW, Duncan D, Helton S, Hutcheson S, Kurundkar D, Logsdon NJ, Locy M, Garth J, Denson R, Farver C, Vo HT, King G, Kentrup D, Faul C, Kulkarni T, De Andrade JA, Yu Z, Matalon S, Thannickal VJ, Krick S. Role of fibroblast growth factor 23 and klotho cross talk in idiopathic pulmonary fibrosis. Am J Physiol Lung Cell Mol Physiol 2019; 317:L141-L154. [PMID: 31042083 PMCID: PMC6689746 DOI: 10.1152/ajplung.00246.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 04/10/2019] [Accepted: 04/28/2019] [Indexed: 01/24/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia that mainly affects the elderly. Several reports have demonstrated that aging is involved in the underlying pathogenic mechanisms of IPF. α-Klotho (KL) has been well characterized as an "age-suppressing" hormone and can provide protection against cellular senescence and oxidative stress. In this study, KL levels were assessed in human plasma and primary lung fibroblasts from patients with idiopathic pulmonary fibrosis (IPF-FB) and in lung tissue from mice exposed to bleomycin, which showed significant downregulation when compared with controls. Conversely, transgenic mice overexpressing KL were protected against bleomycin-induced lung fibrosis. Treatment of human lung fibroblasts with recombinant KL alone was not sufficient to inhibit transforming growth factor-β (TGF-β)-induced collagen deposition and inflammatory marker expression. Interestingly, fibroblast growth factor 23 (FGF23), a proinflammatory circulating protein for which KL is a coreceptor, was upregulated in IPF and bleomycin lungs. To our surprise, FGF23 and KL coadministration led to a significant reduction in fibrosis and inflammation in IPF-FB; FGF23 administration alone or in combination with KL stimulated KL upregulation. We conclude that in IPF downregulation of KL may contribute to fibrosis and inflammation and FGF23 may act as a compensatory antifibrotic and anti-inflammatory mediator via inhibition of TGF-β signaling. Upon restoration of KL levels, the combination of FGF23 and KL leads to resolution of inflammation and fibrosis. Altogether, these data provide novel insight into the FGF23/KL axis and its antifibrotic/anti-inflammatory properties, which opens new avenues for potential therapies in aging-related diseases like IPF.
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Affiliation(s)
- Jarrod W Barnes
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Dawn Duncan
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Scott Helton
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Samuel Hutcheson
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Deepali Kurundkar
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Naomi J Logsdon
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Morgan Locy
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Jaleesa Garth
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Rebecca Denson
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Carol Farver
- Department of Pathology, Cleveland Clinic , Cleveland, Ohio
| | - Hai T Vo
- Department of Neurobiology, The University of Alabama at Birmingham , Birmingham, Alabama
| | - Gwendalyn King
- Department of Neurobiology, The University of Alabama at Birmingham , Birmingham, Alabama
| | - Dominik Kentrup
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Christian Faul
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Tejaswini Kulkarni
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Joao A De Andrade
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
- Birmingham VA Medical Center , Birmingham, Alabama
| | - Zhihong Yu
- Department of Anesthesiology and Perioperative Medicine (Molecular and Translational Biomedicine), University of Alabama , Birmingham, Alabama
| | - Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine (Molecular and Translational Biomedicine), University of Alabama , Birmingham, Alabama
| | - Victor J Thannickal
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
| | - Stefanie Krick
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama , Birmingham, Alabama
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Wright JD, An SW, Xie J, Lim C, Huang CL. Soluble klotho regulates TRPC6 calcium signaling via lipid rafts, independent of the FGFR-FGF23 pathway. FASEB J 2019; 33:9182-9193. [PMID: 31063704 DOI: 10.1096/fj.201900321r] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Soluble klotho (sKlotho), the shed ectodomain of α-klotho, protects the heart by down-regulating transient receptor potential canonical isoform 6 (TRPC6)-mediated calcium signaling. Binding to α2-3-sialyllactose moiety of gangliosides in lipid rafts and inhibition of raft-dependent signaling underlies the mechanism. A recent 3-Å X-ray structure of sKlotho in complex with fibroblast growth factor receptor (FGFR) and fibroblast growth factor 23 (FGF23) indicates that its β6α6 loop might block access to the proposed binding site for α2-3-sialyllactose. It was concluded that sKlotho only functions in complex with FGFR and FGF23 and that sKlotho's pleiotropic effects all depend on FGF23. Here, we report that sKlotho can inhibit TRPC6 channels expressed in cells lacking endogenous FGFRs. Structural modeling and molecular docking show that a repositioned β6α6 loop allows sKlotho to bind α2-3-sialyllactose. Molecular dynamic simulations further show the α2-3-sialyllactose-bound sKlotho complex to be stable. Domains mimicking sKlotho's sialic acid-recognizing activity inhibit TRPC6. The results strongly support the hypothesis that sKlotho can exert effects independent of FGF23 and FGFR.-Wright, J. D., An, S.-W., Xie, J., Lim, C., Huang, C.-L. Soluble klotho regulates TRPC6 calcium signaling via lipid rafts, independent of the FGFR-FGF23 pathway.
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Affiliation(s)
- Jon D Wright
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Sung-Wan An
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA; and
| | - Jian Xie
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA; and
| | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Chou-Long Huang
- Division of Nephrology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA; and
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Martín-González C, González-Reimers E, Quintero-Platt G, Martínez-Riera A, Santolaria-Fernández F. Soluble α-Klotho in Liver Cirrhosis and Alcoholism. Alcohol Alcohol 2019; 54:204-208. [PMID: 30860544 DOI: 10.1093/alcalc/agz019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 02/21/2019] [Indexed: 11/13/2022] Open
Abstract
AIMS AND BACKGROUND Alpha Klotho is a transmembrane protein that serves as co-receptor for FGF23. Ectodomain of membrane bound α Klotho may be shed by membrane bound proteases (activated, among other factors, by tumor necrosis factor (TNF)-α) generating the soluble form of the protein (sKl) that functions as a hormone by itself. It modulates calcium influx into cells, blunts IGF-1/Insulin signaling, promotes synthesis of antioxidants, generally slows down tumor progression, delays cell senescence, is neuroprotective and promotes oligodendrocyte maturation and myelin synthesis, and muscle rejuvenation. It may be involved in inflammation and exerts antifibrogenic effects. Some of these pathways may become altered in alcoholism or liver cirrhosis, but data are scattered and scarce and an update is required. METHOD Literature survey. RESULTS AND CONCLUSIONS Alcohol consumption in non-alcoholics is inversely related to sKl, but alcoholic cirrhotics showed higher-than-normal sKl values in association with liver function derangement. In hepatoma cells, the intensity of Klotho staining was related to faster tumor progression and a shortened life span. Among severe alcoholic cirrhotics sKl is directly related to serum TNF-α levels, and, inversely, to brain atrophy. Given the antioxidant, anti-inflammatory, and antifibrogenic effects of Klotho, perhaps the increase in cirrhosis (and in other inflammatory conditions, such as sepsis or cancer) reflects an attempt to regulate increased inflammation, but clinical and experimental research is urgently needed in this field.
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Affiliation(s)
- C Martín-González
- Servicio de Medicina Interna. Hospital Universitario de Canarias. Universidad de La Laguna. Tenerife, Canary Islands, Spain
| | - E González-Reimers
- Servicio de Medicina Interna. Hospital Universitario de Canarias. Universidad de La Laguna. Tenerife, Canary Islands, Spain
| | - G Quintero-Platt
- Servicio de Medicina Interna. Hospital Universitario de Canarias. Universidad de La Laguna. Tenerife, Canary Islands, Spain
| | - A Martínez-Riera
- Servicio de Medicina Interna. Hospital Universitario de Canarias. Universidad de La Laguna. Tenerife, Canary Islands, Spain
| | - F Santolaria-Fernández
- Servicio de Medicina Interna. Hospital Universitario de Canarias. Universidad de La Laguna. Tenerife, Canary Islands, Spain
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Silva AP, Mendes F, Carias E, Gonçalves RB, Fragoso A, Dias C, Tavares N, Café HM, Santos N, Rato F, Leão Neves P, Almeida E. Plasmatic Klotho and FGF23 Levels as Biomarkers of CKD-Associated Cardiac Disease in Type 2 Diabetic Patients. Int J Mol Sci 2019; 20:E1536. [PMID: 30934737 PMCID: PMC6480092 DOI: 10.3390/ijms20071536] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/20/2019] [Accepted: 03/22/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Research over the past decade has focused on the role of Klotho as a cardio protective agent that prevents the effects of aging on the heart and reduces the burden of cardiovascular disease CVD. The role of the interaction between fibroblast growth factor 23-(FGF-23)/Klotho in Klotho-mediated actions is still under debate. The main objective was to ascertain the potential use of plasmatic Klotho and FGF23 as markers for CKD-associated cardiac disease and mortality. METHODS This was a prospective analysis conducted in an outpatient diabetic nephropathy clinic, enrolling 107 diabetic patients with stage 2⁻3 CKD. Patients were divided into three groups according to their left ventricular mass index and relative wall thickness. RESULTS Multinomial regression analysis demonstrated that low Klotho and higher FGF-23 levels were linked to a greater risk of concentric hypertrophy. In the generalized linear model (GLM), Klotho, FGF-23 and cardiac geometry groups were statistically significant as independent variables of cardiovascular hospitalization (p = 0.007). According to the Cox regression model, fatal cardiovascular events were associated with the following cardiac geometric classifications; eccentric hypertrophy (p = 0.050); concentric hypertrophy (p = 0.041), and serum phosphate ≥ 3.6 mg/dL (p = 0.025), FGF-23 ≥ 168 (p = 0.0149), α-klotho < 313 (p = 0.044). CONCLUSIONS In our population, Klotho and FGF23 are associated with cardiovascular risk in the early stages of CKD.
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Affiliation(s)
- Ana Paula Silva
- Nephrology Department, Centro Hospitalar Universitário do Algarve, 800-836 Faro, Portugal.
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 8005-139 Faro, Portugal.
| | - Filipa Mendes
- Nephrology Department, Centro Hospitalar Universitário do Algarve, 800-836 Faro, Portugal.
| | - Eduarda Carias
- Nephrology Department, Centro Hospitalar Universitário do Algarve, 800-836 Faro, Portugal.
| | - Rui Baptista Gonçalves
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 8005-139 Faro, Portugal.
| | - André Fragoso
- Nephrology Department, Centro Hospitalar Universitário do Algarve, 800-836 Faro, Portugal.
| | - Carolina Dias
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 8005-139 Faro, Portugal.
| | - Nelson Tavares
- Cardiology Department, Centro Hospitalar Universitário do Algarve, 8000-386 Faro, Portugal.
| | - Hugo Mendonça Café
- Cardiology Department, Centro Hospitalar Universitário do Algarve, 8000-386 Faro, Portugal.
| | - Nélio Santos
- Clinic Pathology Department, Centro Hospitalar Universitário do Algarve, 8000-836, Faro, Portugal.
| | - Fátima Rato
- Clinic Pathology Department, Centro Hospitalar Universitário do Algarve, 8000-836, Faro, Portugal.
| | - Pedro Leão Neves
- Nephrology Department, Centro Hospitalar Universitário do Algarve, 800-836 Faro, Portugal.
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 8005-139 Faro, Portugal.
| | - Edgar Almeida
- Faculdadade de Medicina da Universidade de Lisboa, 1600-190 Lisboa, Portugal.
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Abstract
Purpose of review α-Klotho (Klotho) occurs in three isoforms, a membrane-bound form acting as a coreceptor for fibroblast growth factor-23 (FGF23) signalling, a shed soluble form consisting of Klotho's large ectodomain thought to act as an enzyme or a hormone, and a secreted truncated form generated by alternative splicing of the Klotho mRNA with unknown function. The purpose of this review is to highlight the recent advances in our understanding of Klotho's function in mineral homeostasis. Recent findings A number of seminal discoveries have recently been made in this area, shifting existing paradigms. The crystal structure of the ternary FGF receptor (FGFR)-1c/Klotho/FGF23 complex has been uncovered, revealing how the ligand FGF23 interacts with FGFR1c and the coreceptor Klotho at atomic resolution. Furthermore, it was shown that soluble Klotho lacks any glycosidase activity and serves as a bona fide coreceptor for FGF23 signalling. Experiments with a combination of Klotho and Fgf23-deficient mouse models demonstrated that all isoforms of Klotho lack any physiologically relevant, FGF23-independent functions in mineral homeostasis or ageing. Finally, it was demonstrated that the alternatively spliced Klotho mRNA is degraded and is not translated into a secreted Klotho protein isoform in humans. Summary Taken together, there is now overwhelming evidence that the main physiological function of transmembrane and soluble Klotho for mineral homeostasis is their role as coreceptors mediating FGF23 actions. In light of these findings, the main pathophysiological consequence of the downregulation of Klotho observed in acute and chronic renal failure may be the induction of renal FGF23 resistance.
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The Role of the Anti-Aging Protein Klotho in IGF-1 Signaling and Reticular Calcium Leak: Impact on the Chemosensitivity of Dedifferentiated Liposarcomas. Cancers (Basel) 2018; 10:cancers10110439. [PMID: 30441794 PMCID: PMC6266342 DOI: 10.3390/cancers10110439] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 11/09/2018] [Indexed: 01/23/2023] Open
Abstract
By inhibiting Insulin-Like Growth Factor-1-Receptor (IGF-1R) signaling, Klotho (KL) acts like an aging- and tumor-suppressor. We investigated whether KL impacts the aggressiveness of liposarcomas, in which IGF-1R signaling is frequently upregulated. Indeed, we observed that a higher KL expression in liposarcomas is associated with a better outcome for patients. Moreover, KL is downregulated in dedifferentiated liposarcomas (DDLPS) compared to well-differentiated tumors and adipose tissue. Because DDLPS are high-grade tumors associated with poor prognosis, we examined the potential of KL as a tool for overcoming therapy resistance. First, we confirmed the attenuation of IGF-1-induced calcium (Ca2+)-response and Extracellular signal-Regulated Kinase 1/2 (ERK1/2) phosphorylation in KL-overexpressing human DDLPS cells. KL overexpression also reduced cell proliferation, clonogenicity, and increased apoptosis induced by gemcitabine, thapsigargin, and ABT-737, all of which are counteracted by IGF-1R-dependent signaling and activate Ca2+-dependent endoplasmic reticulum (ER) stress. Then, we monitored cell death and cytosolic Ca2+-responses and demonstrated that KL increases the reticular Ca2+-leakage by maintaining TRPC6 at the ER and opening the translocon. Only the latter is necessary for sensitizing DDLPS cells to reticular stressors. This was associated with ERK1/2 inhibition and could be mimicked with IGF-1R or MEK inhibitors. These observations provide a new therapeutic strategy in the management of DDLPS.
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Abstract
Global depletion of klotho accelerates aging, whereas klotho overexpression counteracts aging-related impairments. Why klotho is expressed at much higher levels in the choroid plexus than in other brain regions is unknown. We demonstrate in mice that aging is associated with klotho depletion in the choroid plexus. Reducing klotho selectively within the choroid plexus triggered inflammation within this structure and enhanced activation of innate immune cells within an adjacent brain region following a peripheral immune challenge. In cell culture, we identified a signaling pathway by which klotho suppresses activation of macrophages. Our findings shed light on klotho functions in the choroid plexus and provide a plausible mechanism by which klotho depletion from this structure promotes brain inflammation during the aging process. Located within the brain’s ventricles, the choroid plexus produces cerebrospinal fluid and forms an important barrier between the central nervous system and the blood. For unknown reasons, the choroid plexus produces high levels of the protein klotho. Here, we show that these levels naturally decline with aging. Depleting klotho selectively from the choroid plexus via targeted viral vector-induced knockout in Klothoflox/flox mice increased the expression of multiple proinflammatory factors and triggered macrophage infiltration of this structure in young mice, simulating changes in unmanipulated old mice. Wild-type mice infected with the same Cre recombinase-expressing virus did not show such alterations. Experimental depletion of klotho from the choroid plexus enhanced microglial activation in the hippocampus after peripheral injection of mice with lipopolysaccharide. In primary cultures, klotho suppressed thioredoxin-interacting protein-dependent activation of the NLRP3 inflammasome in macrophages by enhancing fibroblast growth factor 23 signaling. We conclude that klotho functions as a gatekeeper at the interface between the brain and immune system in the choroid plexus. Klotho depletion in aging or disease may weaken this barrier and promote immune-mediated neuropathogenesis.
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